christopher/rosetta-code · Datasets at Hugging Face

task_url stringlengths 30 116	task_name stringlengths 2 86	task_description stringlengths 0 14.4k	language_url stringlengths 2 53	language_name stringlengths 1 52	code stringlengths 0 61.9k
http://rosettacode.org/wiki/Rot-13	Rot-13	Task Implement a rot-13 function (or procedure, class, subroutine, or other "callable" object as appropriate to your programming environment). Optionally wrap this function in a utility program (like tr, which acts like a common UNIX utility, performing a line-by-line rot-13 encoding of every line of input contained in each file listed on its command line, or (if no filenames are passed thereon) acting as a filter on its "standard input." (A number of UNIX scripting languages and utilities, such as awk and sed either default to processing files in this way or have command line switches or modules to easily implement these wrapper semantics, e.g., Perl and Python). The rot-13 encoding is commonly known from the early days of Usenet "Netnews" as a way of obfuscating text to prevent casual reading of spoiler or potentially offensive material. Many news reader and mail user agent programs have built-in rot-13 encoder/decoders or have the ability to feed a message through any external utility script for performing this (or other) actions. The definition of the rot-13 function is to simply replace every letter of the ASCII alphabet with the letter which is "rotated" 13 characters "around" the 26 letter alphabet from its normal cardinal position (wrapping around from z to a as necessary). Thus the letters abc become nop and so on. Technically rot-13 is a "mono-alphabetic substitution cipher" with a trivial "key". A proper implementation should work on upper and lower case letters, preserve case, and pass all non-alphabetic characters in the input stream through without alteration. Related tasks Caesar cipher Substitution Cipher Vigenère Cipher/Cryptanalysis Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet	#Simula	Simula	TEXT PROCEDURE ROT13(INP); TEXT INP; BEGIN CHARACTER PROCEDURE ROT13CHAR(C); CHARACTER C; ROT13CHAR := CHAR( RANK(C) + (IF C >= 'A' AND C <= 'M' THEN 13 ELSE IF C >= 'a' AND C <= 'm' THEN 13 ELSE IF C >= 'N' AND C <= 'Z' THEN -13 ELSE IF C >= 'n' AND C <= 'z' THEN -13 ELSE 0)); TEXT OUTP; OUTP :- BLANKS(INP.LENGTH); INP.SETPOS(1); WHILE INP.MORE DO OUTP.PUTCHAR(ROT13CHAR(INP.GETCHAR)); ROT13 :- OUTP; END ROT13;
http://rosettacode.org/wiki/Roman_numerals/Encode	Roman numerals/Encode	Task Create a function taking a positive integer as its parameter and returning a string containing the Roman numeral representation of that integer. Modern Roman numerals are written by expressing each digit separately, starting with the left most digit and skipping any digit with a value of zero. In Roman numerals: 1990 is rendered: 1000=M, 900=CM, 90=XC; resulting in MCMXC 2008 is written as 2000=MM, 8=VIII; or MMVIII 1666 uses each Roman symbol in descending order: MDCLXVI	#SenseTalk	SenseTalk	function RomanNumeralsEncode number put [ (1, "I"), (4, "IV"), (5, "V"), (9, "IX"), (10, "X"), (40, "XL"), (50, "L"), (90, "XC"), (100, "C"), (400, "CD"), (500, "D"), (900, "CM"), (1000, "M") ] into values repeat for index = each item of (the number of items in values)..1 put item index of values into pair repeat while number is greater than or equal to the first item of pair put the second item of pair after numerals subtract the first item of pair from number end repeat end repeat return numerals end RomanNumeralsEncode
http://rosettacode.org/wiki/Roman_numerals/Decode	Roman numerals/Decode	Task Create a function that takes a Roman numeral as its argument and returns its value as a numeric decimal integer. You don't need to validate the form of the Roman numeral. Modern Roman numerals are written by expressing each decimal digit of the number to be encoded separately, starting with the leftmost decimal digit and skipping any 0s (zeroes). 1990 is rendered as MCMXC (1000 = M, 900 = CM, 90 = XC) and 2008 is rendered as MMVIII (2000 = MM, 8 = VIII). The Roman numeral for 1666, MDCLXVI, uses each letter in descending order.	#XPL0	XPL0	string 0; \use zero-terminated strings code CrLf=9, IntOut=11; func Roman(Str); \Convert Roman numeral string to decimal value char Str; int I, Val, Val0, Sum; [I:= 0; Sum:= 0; Val0:= 5000; loop [case Str(I) of ^M: Val:= 1000; ^D: Val:= 500; ^C: Val:= 100; ^L: Val:= 50; ^X: Val:= 10; ^V: Val:= 5; ^I: Val:= 1 other return Sum; \zero string terminator I:= I+1; Sum:= Sum + Val; if Val > Val0 then Sum:= Sum - 2*Val0; Val0:= Val; ]; ]; [IntOut(0, Roman("MCMXC")); CrLf(0); IntOut(0, Roman("MMVIII")); CrLf(0); IntOut(0, Roman("MDCLXVI")); CrLf(0); ]
http://rosettacode.org/wiki/Repeat_a_string	Repeat a string	Take a string and repeat it some number of times. Example: repeat("ha", 5) => "hahahahaha" If there is a simpler/more efficient way to repeat a single “character” (i.e. creating a string filled with a certain character), you might want to show that as well (i.e. repeat-char("", 5) => "****"). Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet	#Free_Pascal	Free Pascal	strUtils.dupeString('ha', 5)
http://rosettacode.org/wiki/Repeat_a_string	Repeat a string	Take a string and repeat it some number of times. Example: repeat("ha", 5) => "hahahahaha" If there is a simpler/more efficient way to repeat a single “character” (i.e. creating a string filled with a certain character), you might want to show that as well (i.e. repeat-char("", 5) => "****"). Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet	#FreeBASIC	FreeBASIC	' FB 1.05.0 Win64 ' A character is essentially a string of length 1 in FB though there is a built-in function, String, ' which creates a string by repeating a character a given number of times. ' To avoid repeated concatenation (a slow operation) when the string to be repeated has a length ' greater than one, we instead create a buffer of the required size and then fill that. Function repeat(s As String, n As Integer) As String If n < 1 Then Return "" If n = 1 Then Return s Var size = Len(s) If size = 0 Then Return s ' empty string If size = 1 Then Return String(n, s[0]) ' repeated single character Var buffer = Space(size * n) 'create buffer for size > 1 For i As Integer = 0 To n - 1 For j As Integer = 0 To size - 1 buffer[i * size + j] = s[j] Next j Next i Return buffer End Function Print repeat("rosetta", 1) Print repeat("ha", 5) Print repeat("*", 5) Print Print "Press any key to quit program" Sleep
http://rosettacode.org/wiki/Return_multiple_values	Return multiple values	Task Show how to return more than one value from a function.	#PHP	PHP	function addsub($x, $y) { return array($x + $y, $x - $y); }
http://rosettacode.org/wiki/Return_multiple_values	Return multiple values	Task Show how to return more than one value from a function.	#Picat	Picat	main => [A,B,C] = fun(10), println([A,B,C]). fun(N) = [2N-1,2N,2*N+1].
http://rosettacode.org/wiki/Remove_duplicate_elements	Remove duplicate elements	Sorting Algorithm This is a sorting algorithm. It may be applied to a set of data in order to sort it. For comparing various sorts, see compare sorts. For other sorting algorithms, see sorting algorithms, or: O(n logn) sorts Heap sort \| Merge sort \| Patience sort \| Quick sort O(n log2n) sorts Shell Sort O(n2) sorts Bubble sort \| Cocktail sort \| Cocktail sort with shifting bounds \| Comb sort \| Cycle sort \| Gnome sort \| Insertion sort \| Selection sort \| Strand sort other sorts Bead sort \| Bogo sort \| Common sorted list \| Composite structures sort \| Custom comparator sort \| Counting sort \| Disjoint sublist sort \| External sort \| Jort sort \| Lexicographical sort \| Natural sorting \| Order by pair comparisons \| Order disjoint list items \| Order two numerical lists \| Object identifier (OID) sort \| Pancake sort \| Quickselect \| Permutation sort \| Radix sort \| Ranking methods \| Remove duplicate elements \| Sleep sort \| Stooge sort \| [Sort letters of a string] \| Three variable sort \| Topological sort \| Tree sort Given an Array, derive a sequence of elements in which all duplicates are removed. There are basically three approaches seen here: Put the elements into a hash table which does not allow duplicates. The complexity is O(n) on average, and O(n2) worst case. This approach requires a hash function for your type (which is compatible with equality), either built-in to your language, or provided by the user. Sort the elements and remove consecutive duplicate elements. The complexity of the best sorting algorithms is O(n log n). This approach requires that your type be "comparable", i.e., have an ordering. Putting the elements into a self-balancing binary search tree is a special case of sorting. Go through the list, and for each element, check the rest of the list to see if it appears again, and discard it if it does. The complexity is O(n2). The up-shot is that this always works on any type (provided that you can test for equality).	#Elixir	Elixir	defmodule RC do # Set approach def uniq1(list), do: MapSet.new(list) \|> MapSet.to_list # Sort approach def uniq2(list), do: Enum.sort(list) \|> Enum.dedup # Go through the list approach def uniq3(list), do: uniq3(list, []) defp uniq3([], res), do: Enum.reverse(res) defp uniq3([h\|t], res) do if h in res, do: uniq3(t, res), else: uniq3(t, [h \| res]) end end num = 10000 max = div(num, 10) list = for _ <- 1..num, do: :rand.uniform(max) funs = [&Enum.uniq/1, &RC.uniq1/1, &RC.uniq2/1, &RC.uniq3/1] Enum.each(funs, fn fun -> result = fun.([1,1,2,1,'redundant',1.0,[1,2,3],[1,2,3],'redundant',1.0]) :timer.tc(fn -> Enum.each(1..100, fn _ -> fun.(list) end) end) \|> fn{t,_} -> IO.puts "#{inspect fun}:\t#{t/1000000}\t#{inspect result}" end.() end)
http://rosettacode.org/wiki/Recaman%27s_sequence	Recaman's sequence	The Recamán's sequence generates Natural numbers. Starting from a(0)=0, the n'th term a(n), where n>0, is the previous term minus n i.e a(n) = a(n-1) - n but only if this is both positive and has not been previousely generated. If the conditions don't hold then a(n) = a(n-1) + n. Task Generate and show here the first 15 members of the sequence. Find and show here, the first duplicated number in the sequence. Optionally: Find and show here, how many terms of the sequence are needed until all the integers 0..1000, inclusive, are generated. References A005132, The On-Line Encyclopedia of Integer Sequences. The Slightly Spooky Recamán Sequence, Numberphile video. Recamán's sequence, on Wikipedia.	#Phix	Phix	with javascript_semantics bool found_duplicate = false sequence a = {0}, used = {} -- (grows to 1,942,300 entries) integer all_used = 0, n = 1, next, prev = 0 while n<=15 or not found_duplicate or all_used<1000 do next = prev - n if next<1 or (next<=length(used) and used[next]) then next = prev + n end if a &= next integer padlen = next-length(used) bool already_used = padlen<=0 and used[next] if not already_used then if padlen>0 then used &= repeat(false,padlen) end if used[next] = true while all_used<length(used) and used[all_used+1] do all_used += 1 end while end if if length(a)=15 then printf(1,"The first 15 terms of the Recaman sequence are: %v\n",{a}) end if if already_used and not found_duplicate then printf(1,"The first duplicated term is a[%d] = %d\n", {n, next}) found_duplicate = true; end if if all_used>=1000 then printf(1,"Terms up to a[%d] are needed to generate 0 to 1000\n", {n}); end if prev = next n += 1 end while
http://rosettacode.org/wiki/Reduced_row_echelon_form	Reduced row echelon form	Reduced row echelon form You are encouraged to solve this task according to the task description, using any language you may know. Task Show how to compute the reduced row echelon form (a.k.a. row canonical form) of a matrix. The matrix can be stored in any datatype that is convenient (for most languages, this will probably be a two-dimensional array). Built-in functions or this pseudocode (from Wikipedia) may be used: function ToReducedRowEchelonForm(Matrix M) is lead := 0 rowCount := the number of rows in M columnCount := the number of columns in M for 0 ≤ r < rowCount do if columnCount ≤ lead then stop end if i = r while M[i, lead] = 0 do i = i + 1 if rowCount = i then i = r lead = lead + 1 if columnCount = lead then stop end if end if end while Swap rows i and r If M[r, lead] is not 0 divide row r by M[r, lead] for 0 ≤ i < rowCount do if i ≠ r do Subtract M[i, lead] multiplied by row r from row i end if end for lead = lead + 1 end for end function For testing purposes, the RREF of this matrix: 1 2 -1 -4 2 3 -1 -11 -2 0 -3 22 is: 1 0 0 -8 0 1 0 1 0 0 1 -2	#Haskell	Haskell	import Data.List (find) rref :: Fractional a => [[a]] -> [[a]] rref m = f m 0 [0 .. rows - 1] where rows = length m cols = length $ head m f m _ [] = m f m lead (r : rs) \| indices == Nothing = m \| otherwise = f m' (lead' + 1) rs where indices = find p l p (col, row) = m !! row !! col /= 0 l = [(col, row) \| col <- [lead .. cols - 1], row <- [r .. rows - 1]] Just (lead', i) = indices newRow = map (/ m !! i !! lead') $ m !! i m' = zipWith g [0..] $ replace r newRow $ replace i (m !! r) m g n row \| n == r = row \| otherwise = zipWith h newRow row where h = subtract . (* row !! lead') replace :: Int -> a -> [a] -> [a] {- Replaces the element at the given index. -} replace n e l = a ++ e : b where (a, _ : b) = splitAt n l
http://rosettacode.org/wiki/Real_constants_and_functions	Real constants and functions	Task Show how to use the following math constants and functions in your language (if not available, note it): e (base of the natural logarithm) π {\displaystyle \pi } square root logarithm (any base allowed) exponential (ex ) absolute value (a.k.a. "magnitude") floor (largest integer less than or equal to this number--not the same as truncate or int) ceiling (smallest integer not less than this number--not the same as round up) power (xy ) Related task Trigonometric Functions	#Elm	Elm	e -- e pi -- pi sqrt x -- square root logBase 3 9 -- logarithm (any base) e^x -- exponential abs x -- absolute value floor x -- floor ceiling x -- ceiling 2 ^ 3 -- power
http://rosettacode.org/wiki/Real_constants_and_functions	Real constants and functions	Task Show how to use the following math constants and functions in your language (if not available, note it): e (base of the natural logarithm) π {\displaystyle \pi } square root logarithm (any base allowed) exponential (ex ) absolute value (a.k.a. "magnitude") floor (largest integer less than or equal to this number--not the same as truncate or int) ceiling (smallest integer not less than this number--not the same as round up) power (xy ) Related task Trigonometric Functions	#Erlang	Erlang	% Implemented by Arjun Sunel -module(math_constants). -export([main/0]). main() -> io:format("~p~n", [math:exp(1)] ), % e io:format("~p~n", [math:pi()] ), % pi io:format("~p~n", [math:sqrt(16)] ), % square root io:format("~p~n", [math:log(10)] ), % natural logarithm io:format("~p~n", [math:log10(10)] ), % base 10 logarithm io:format("~p~n", [math:exp(2)] ), % e raised to the power of x io:format("~p~n", [abs(-2.24)] ), % absolute value io:format("~p~n", [floor(3.1423)] ), % floor io:format("~p~n", [ceil(20.125)] ), % ceiling io:format("~p~n", [math:pow(3,2)] ). % exponentiation floor(X) when X < 0 -> T = trunc(X), case X - T == 0 of true -> T; false -> T - 1 end; floor(X) -> trunc(X). ceil(X) when X < 0 -> trunc(X); ceil(X) -> T = trunc(X), case X - T == 0 of true -> T; false -> T + 1 end.
http://rosettacode.org/wiki/Remove_lines_from_a_file	Remove lines from a file	Task Remove a specific line or a number of lines from a file. This should be implemented as a routine that takes three parameters (filename, starting line, and the number of lines to be removed). For the purpose of this task, line numbers and the number of lines start at one, so to remove the first two lines from the file foobar.txt, the parameters should be: foobar.txt, 1, 2 Empty lines are considered and should still be counted, and if the specified line is empty, it should still be removed. An appropriate message should appear if an attempt is made to remove lines beyond the end of the file.	#Lua	Lua	function remove( filename, starting_line, num_lines ) local fp = io.open( filename, "r" ) if fp == nil then return nil end content = {} i = 1; for line in fp:lines() do if i < starting_line or i >= starting_line + num_lines then content[#content+1] = line end i = i + 1 end if i > starting_line and i < starting_line + num_lines then print( "Warning: Tried to remove lines after EOF." ) end fp:close() fp = io.open( filename, "w+" ) for i = 1, #content do fp:write( string.format( "%s\n", content[i] ) ) end fp:close() end
http://rosettacode.org/wiki/Read_entire_file	Read entire file	Task Load the entire contents of some text file as a single string variable. If applicable, discuss: encoding selection, the possibility of memory-mapping. Of course, in practice one should avoid reading an entire file at once if the file is large and the task can be accomplished incrementally instead (in which case check File IO); this is for those cases where having the entire file is actually what is wanted.	#FutureBasic	FutureBasic	_window = 1 begin enum 1 _scrollView _textView end enum void local fn BuildWindow CGRect r = {0,0,550,400} window _window, @"Read Entire File", r scrollview _scrollView, r ViewSetAutoresizingMask( _scrollView, NSViewWidthSizable + NSViewHeightSizable ) textview _textView,, _scrollView end fn local fn ReadTextFile CFStringRef string CFURLRef url = openpanel 1, @"Select text file..." if ( url ) string = fn StringWithContentsOfURL( url, NSUTF8StringEncoding, NULL ) TextSetString( _textView, string ) else // user cancelled end if end fn fn BuildWindow fn ReadTextFile HandleEvents
http://rosettacode.org/wiki/Read_entire_file	Read entire file	Task Load the entire contents of some text file as a single string variable. If applicable, discuss: encoding selection, the possibility of memory-mapping. Of course, in practice one should avoid reading an entire file at once if the file is large and the task can be accomplished incrementally instead (in which case check File IO); this is for those cases where having the entire file is actually what is wanted.	#Gambas	Gambas	Public Sub Form_Open() Dim sFile As String sFile = File.Load(User.home &/ "file.txt") End
http://rosettacode.org/wiki/Rep-string	Rep-string	Given a series of ones and zeroes in a string, define a repeated string or rep-string as a string which is created by repeating a substring of the first N characters of the string truncated on the right to the length of the input string, and in which the substring appears repeated at least twice in the original. For example, the string 10011001100 is a rep-string as the leftmost four characters of 1001 are repeated three times and truncated on the right to give the original string. Note that the requirement for having the repeat occur two or more times means that the repeating unit is never longer than half the length of the input string. Task Write a function/subroutine/method/... that takes a string and returns an indication of if it is a rep-string and the repeated string. (Either the string that is repeated, or the number of repeated characters would suffice). There may be multiple sub-strings that make a string a rep-string - in that case an indication of all, or the longest, or the shortest would suffice. Use the function to indicate the repeating substring if any, in the following: 1001110011 1110111011 0010010010 1010101010 1111111111 0100101101 0100100 101 11 00 1 Show your output on this page. Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet	#Perl	Perl	foreach (qw(1001110011 1110111011 0010010010 1010101010 1111111111 0100101101 0100100 101 11 00 1)) { print "$_\n"; if (/^(.+)\1+(.*$)(?(?{ substr($1, 0, length $2) eq $2 })\|(?!))/) { print ' ' x length $1, "$1\n\n"; } else { print " (no repeat)\n\n"; } }
http://rosettacode.org/wiki/Rep-string	Rep-string	Given a series of ones and zeroes in a string, define a repeated string or rep-string as a string which is created by repeating a substring of the first N characters of the string truncated on the right to the length of the input string, and in which the substring appears repeated at least twice in the original. For example, the string 10011001100 is a rep-string as the leftmost four characters of 1001 are repeated three times and truncated on the right to give the original string. Note that the requirement for having the repeat occur two or more times means that the repeating unit is never longer than half the length of the input string. Task Write a function/subroutine/method/... that takes a string and returns an indication of if it is a rep-string and the repeated string. (Either the string that is repeated, or the number of repeated characters would suffice). There may be multiple sub-strings that make a string a rep-string - in that case an indication of all, or the longest, or the shortest would suffice. Use the function to indicate the repeating substring if any, in the following: 1001110011 1110111011 0010010010 1010101010 1111111111 0100101101 0100100 101 11 00 1 Show your output on this page. Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet	#Phix	Phix	function list_reps(string r) sequence replist = {} integer n = length(r) for m=1 to floor(n/2) do string s = r[1..m] if join(repeat(s,floor(n/m)+1),"")[1..n]=r then replist = append(replist,s) end if end for return replist end function constant tests = {"1001110011", "1110111011", "0010010010", "1010101010", "1111111111", "0100101101", "0100100", "101", "11", "00", "1"} for i=1 to length(tests) do printf(1,"%s\n",{tests[i]}) sequence replist = list_reps(tests[i]) if length(replist)=0 then printf(1,"not a rep-string.\n") else for j=1 to length(replist) do string rj = replist[j], pad = repeat(' ',length(rj)) printf(1,"%s%s\n",{pad,rj}) end for end if printf(1,"\n") end for
http://rosettacode.org/wiki/Regular_expressions	Regular expressions	Task match a string against a regular expression substitute part of a string using a regular expression	#OCaml	OCaml	#load "str.cma";; let str = "I am a string";; try ignore(Str.search_forward (Str.regexp ".*string$") str 0); print_endline "ends with 'string'" with Not_found -> () ;;
http://rosettacode.org/wiki/Regular_expressions	Regular expressions	Task match a string against a regular expression substitute part of a string using a regular expression	#Ol	Ol	; matching: (define regex (string->regex "m/aa(bb\|cc)dd/")) (print (regex "aabbddx")) ; => true (print (regex "aaccddx")) ; => true (print (regex "aabcddx")) ; => false ; substitute part of a string: (define regex (string->regex "s/aa(bb\|cc)dd/HAHAHA/")) (print (regex "aabbddx")) ; => HAHAHAx (print (regex "aaccddx")) ; => HAHAHAx (print (regex "aabcddx")) ; => false
http://rosettacode.org/wiki/Reverse_a_string	Reverse a string	Task Take a string and reverse it. For example, "asdf" becomes "fdsa". Extra credit Preserve Unicode combining characters. For example, "as⃝df̅" becomes "f̅ds⃝a", not "̅fd⃝sa". Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet	#CLU	CLU	reverse = proc (s: string) returns (string) rslt: array[char] := array[char]$predict(1,string$size(s)) for c: char in string$chars(s) do array[char]$addl(rslt,c) end return(string$ac2s(rslt)) end reverse start_up = proc () po: stream := stream$primary_output() stream$putl(po, reverse("!dlrow ,olleH")) end start_up
http://rosettacode.org/wiki/Repeat	Repeat	Task Write a procedure which accepts as arguments another procedure and a positive integer. The latter procedure is executed a number of times equal to the accepted integer.	#Stata	Stata	function repeat(f,n) { for (i=1; i<=n; i++) (*f)() } function hello() { printf("Hello\n") } repeat(&hello(),3)
http://rosettacode.org/wiki/Repeat	Repeat	Task Write a procedure which accepts as arguments another procedure and a positive integer. The latter procedure is executed a number of times equal to the accepted integer.	#Swift	Swift	func repeat(n: Int, f: () -> ()) { for _ in 0..<n { f() } } repeat(4) { println("Example") }
http://rosettacode.org/wiki/Rename_a_file	Rename a file	Task Rename: a file called input.txt into output.txt and a directory called docs into mydocs. This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root. It can be assumed that the user has the rights to do so. (In unix-type systems, only the user root would have sufficient permissions in the filesystem root.)	#PHP	PHP	<?php rename('input.txt', 'output.txt'); rename('docs', 'mydocs'); rename('/input.txt', '/output.txt'); rename('/docs', '/mydocs'); ?>
http://rosettacode.org/wiki/Rename_a_file	Rename a file	Task Rename: a file called input.txt into output.txt and a directory called docs into mydocs. This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root. It can be assumed that the user has the rights to do so. (In unix-type systems, only the user root would have sufficient permissions in the filesystem root.)	#PicoLisp	PicoLisp	(call 'mv "input.txt" "output.txt") (call 'mv "docs" "mydocs") (call 'mv "/input.txt" "/output.txt") (call 'mv "/docs" "/mydocs")
http://rosettacode.org/wiki/Rename_a_file	Rename a file	Task Rename: a file called input.txt into output.txt and a directory called docs into mydocs. This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root. It can be assumed that the user has the rights to do so. (In unix-type systems, only the user root would have sufficient permissions in the filesystem root.)	#Pike	Pike	int main(){ mv("input.txt", "output.txt"); mv("/input.txt", "/output.txt"); mv("docs", "mydocs"); mv("/docs", "/mydocs"); }
http://rosettacode.org/wiki/Reverse_words_in_a_string	Reverse words in a string	Task Reverse the order of all tokens in each of a number of strings and display the result; the order of characters within a token should not be modified. Example Hey you, Bub! would be shown reversed as: Bub! you, Hey Tokens are any non-space characters separated by spaces (formally, white-space); the visible punctuation form part of the word within which it is located and should not be modified. You may assume that there are no significant non-visible characters in the input. Multiple or superfluous spaces may be compressed into a single space. Some strings have no tokens, so an empty string (or one just containing spaces) would be the result. Display the strings in order (1st, 2nd, 3rd, ···), and one string per line. (You can consider the ten strings as ten lines, and the tokens as words.) Input data (ten lines within the box) line ╔════════════════════════════════════════╗ 1 ║ ---------- Ice and Fire ------------ ║ 2 ║ ║ ◄─── a blank line here. 3 ║ fire, in end will world the say Some ║ 4 ║ ice. in say Some ║ 5 ║ desire of tasted I've what From ║ 6 ║ fire. favor who those with hold I ║ 7 ║ ║ ◄─── a blank line here. 8 ║ ... elided paragraph last ... ║ 9 ║ ║ ◄─── a blank line here. 10 ║ Frost Robert ----------------------- ║ ╚════════════════════════════════════════╝ Cf. Phrase reversals	#OCaml	OCaml	#load "str.cma" let input = ["---------- Ice and Fire ------------"; ""; "fire, in end will world the say Some"; "ice. in say Some"; "desire of tasted I've what From"; "fire. favor who those with hold I"; ""; "... elided paragraph last ..."; ""; "Frost Robert -----------------------"];; let splitted = List.map (Str.split (Str.regexp " ")) input in let reversed = List.map List.rev splitted in let final = List.map (String.concat " ") reversed in List.iter print_endline final;;
http://rosettacode.org/wiki/Rot-13	Rot-13	Task Implement a rot-13 function (or procedure, class, subroutine, or other "callable" object as appropriate to your programming environment). Optionally wrap this function in a utility program (like tr, which acts like a common UNIX utility, performing a line-by-line rot-13 encoding of every line of input contained in each file listed on its command line, or (if no filenames are passed thereon) acting as a filter on its "standard input." (A number of UNIX scripting languages and utilities, such as awk and sed either default to processing files in this way or have command line switches or modules to easily implement these wrapper semantics, e.g., Perl and Python). The rot-13 encoding is commonly known from the early days of Usenet "Netnews" as a way of obfuscating text to prevent casual reading of spoiler or potentially offensive material. Many news reader and mail user agent programs have built-in rot-13 encoder/decoders or have the ability to feed a message through any external utility script for performing this (or other) actions. The definition of the rot-13 function is to simply replace every letter of the ASCII alphabet with the letter which is "rotated" 13 characters "around" the 26 letter alphabet from its normal cardinal position (wrapping around from z to a as necessary). Thus the letters abc become nop and so on. Technically rot-13 is a "mono-alphabetic substitution cipher" with a trivial "key". A proper implementation should work on upper and lower case letters, preserve case, and pass all non-alphabetic characters in the input stream through without alteration. Related tasks Caesar cipher Substitution Cipher Vigenère Cipher/Cryptanalysis Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet	#Slate	Slate	#!/usr/local/bin/slate ch@(String Character traits) rot13 [\| value \| upper ::= ch isUppercase. value := ch toLowercase as: Integer. (value >= 97) /\ [value < 110] ifTrue: [value += 13] ifFalse: [(value > 109) /\ [value <= 122] ifTrue: [value -= 13]]. upper ifTrue: [(value as: String Character) toUppercase] ifFalse: [value as: String Character] ]. lobby define: #Rot13Encoder &parents: {Encoder}. c@(Rot13Encoder traits) convert [ [c in isAtEnd] whileFalse: [c out nextPut: c in next rot13]. ]. (Rot13Encoder newFrom: Console reader to: Console writer) convert.
http://rosettacode.org/wiki/Roman_numerals/Encode	Roman numerals/Encode	Task Create a function taking a positive integer as its parameter and returning a string containing the Roman numeral representation of that integer. Modern Roman numerals are written by expressing each digit separately, starting with the left most digit and skipping any digit with a value of zero. In Roman numerals: 1990 is rendered: 1000=M, 900=CM, 90=XC; resulting in MCMXC 2008 is written as 2000=MM, 8=VIII; or MMVIII 1666 uses each Roman symbol in descending order: MDCLXVI	#SETL	SETL	examples := [2008, 1666, 1990]; for example in examples loop print( roman_numeral(example) ); end loop; proc roman_numeral( n ); R := [[1000, 'M'], [900, 'CM'], [500, 'D'], [400, 'CD'], [100, 'C'], [90, 'XC'], [50, 'L'], [40, 'XL'], [10, 'X'], [9, 'IX'], [5, 'V'], [4, 'IV'], [1, 'I']]; roman := ''; for numeral in R loop while n >= numeral(1) loop n := n - numeral(1); roman := roman + numeral(2); end loop; end loop; return roman; end;
http://rosettacode.org/wiki/Roman_numerals/Decode	Roman numerals/Decode	Task Create a function that takes a Roman numeral as its argument and returns its value as a numeric decimal integer. You don't need to validate the form of the Roman numeral. Modern Roman numerals are written by expressing each decimal digit of the number to be encoded separately, starting with the leftmost decimal digit and skipping any 0s (zeroes). 1990 is rendered as MCMXC (1000 = M, 900 = CM, 90 = XC) and 2008 is rendered as MMVIII (2000 = MM, 8 = VIII). The Roman numeral for 1666, MDCLXVI, uses each letter in descending order.	#XQuery	XQuery	xquery version "3.1"; declare function local:decode-roman-numeral($roman-numeral as xs:string) { $roman-numeral => upper-case() => for-each( function($roman-numeral-uppercase) { analyze-string($roman-numeral-uppercase, ".")/fn:match ! map { "M": 1000, "D": 500, "C": 100, "L": 50, "X": 10, "V": 5, "I": 1 }(.) } ) => fold-right([0,0], function($number as xs:integer, $accumulator as array(*)) { let $running-total := $accumulator?1 let $previous-number := $accumulator?2 return if ($number lt $previous-number) then [ $running-total - $number, $number ] else [ $running-total + $number, $number ] } ) => array:get(1) }; let $roman-numerals := map { "MCMXCIX": 1999, "MDCLXVI": 1666, "XXV": 25, "XIX": 19, "XI": 11, "CMLIV": 954, "MMXI": 2011, "CD": 400, "MCMXC": 1990, "MMVIII": 2008, "MMIX": 2009, "MMMDCCCLXXXVIII": 3888 } return map:for-each( $roman-numerals, function($roman-numeral, $expected-value) { local:decode-roman-numeral($roman-numeral) eq $expected-value } )
http://rosettacode.org/wiki/Repeat_a_string	Repeat a string	Take a string and repeat it some number of times. Example: repeat("ha", 5) => "hahahahaha" If there is a simpler/more efficient way to repeat a single “character” (i.e. creating a string filled with a certain character), you might want to show that as well (i.e. repeat-char("", 5) => "****"). Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet	#Frink	Frink	println[repeat["ha", 5]]
http://rosettacode.org/wiki/Return_multiple_values	Return multiple values	Task Show how to return more than one value from a function.	#PicoLisp	PicoLisp	(de addsub (X Y) (list (+ X Y) (- X Y)) )
http://rosettacode.org/wiki/Return_multiple_values	Return multiple values	Task Show how to return more than one value from a function.	#Pike	Pike	array(int) addsub(int x, int y) { return ({ x+y, x-y }); } [int z, int w] = addsub(5,4);
http://rosettacode.org/wiki/Remove_duplicate_elements	Remove duplicate elements	Sorting Algorithm This is a sorting algorithm. It may be applied to a set of data in order to sort it. For comparing various sorts, see compare sorts. For other sorting algorithms, see sorting algorithms, or: O(n logn) sorts Heap sort \| Merge sort \| Patience sort \| Quick sort O(n log2n) sorts Shell Sort O(n2) sorts Bubble sort \| Cocktail sort \| Cocktail sort with shifting bounds \| Comb sort \| Cycle sort \| Gnome sort \| Insertion sort \| Selection sort \| Strand sort other sorts Bead sort \| Bogo sort \| Common sorted list \| Composite structures sort \| Custom comparator sort \| Counting sort \| Disjoint sublist sort \| External sort \| Jort sort \| Lexicographical sort \| Natural sorting \| Order by pair comparisons \| Order disjoint list items \| Order two numerical lists \| Object identifier (OID) sort \| Pancake sort \| Quickselect \| Permutation sort \| Radix sort \| Ranking methods \| Remove duplicate elements \| Sleep sort \| Stooge sort \| [Sort letters of a string] \| Three variable sort \| Topological sort \| Tree sort Given an Array, derive a sequence of elements in which all duplicates are removed. There are basically three approaches seen here: Put the elements into a hash table which does not allow duplicates. The complexity is O(n) on average, and O(n2) worst case. This approach requires a hash function for your type (which is compatible with equality), either built-in to your language, or provided by the user. Sort the elements and remove consecutive duplicate elements. The complexity of the best sorting algorithms is O(n log n). This approach requires that your type be "comparable", i.e., have an ordering. Putting the elements into a self-balancing binary search tree is a special case of sorting. Go through the list, and for each element, check the rest of the list to see if it appears again, and discard it if it does. The complexity is O(n2). The up-shot is that this always works on any type (provided that you can test for equality).	#Erlang	Erlang	List = [1, 2, 3, 2, 2, 4, 5, 5, 4, 6, 6, 5]. UniqueList = gb_sets:to_list(gb_sets:from_list(List)). % Alternatively the builtin: Unique_list = lists:usort( List ).
http://rosettacode.org/wiki/Recaman%27s_sequence	Recaman's sequence	The Recamán's sequence generates Natural numbers. Starting from a(0)=0, the n'th term a(n), where n>0, is the previous term minus n i.e a(n) = a(n-1) - n but only if this is both positive and has not been previousely generated. If the conditions don't hold then a(n) = a(n-1) + n. Task Generate and show here the first 15 members of the sequence. Find and show here, the first duplicated number in the sequence. Optionally: Find and show here, how many terms of the sequence are needed until all the integers 0..1000, inclusive, are generated. References A005132, The On-Line Encyclopedia of Integer Sequences. The Slightly Spooky Recamán Sequence, Numberphile video. Recamán's sequence, on Wikipedia.	#PHP	PHP	<?php $a = array(); array_push($a, 0); $used = array(); array_push($used, 0); $used1000 = array(); array_push($used1000, 0); $foundDup = false; $n = 1; while($n <= 15 \|\| !$foundDup \|\| count($used1000) < 1001) { $next = $a[$n - 1] - $n; if ($next < 1 \|\| in_array($next, $used)) { $next += 2 * $n; } $alreadyUsed = in_array($next, $used); array_push($a, $next); if (!$alreadyUsed) { array_push($used, $next); if (0 <= $next && $next <= 1000) { array_push($used1000, $next); } } if ($n == 14) { echo "The first 15 terms of the Recaman sequence are : ["; foreach($a as $i => $v) { if ( $i == count($a) - 1) echo "$v"; else echo "$v, "; } echo "]\n"; } if (!$foundDup && $alreadyUsed) { printf("The first duplicate term is a[%d] = %d\n", $n, $next); $foundDup = true; } if (count($used1000) == 1001) { printf("Terms up to a[%d] are needed to generate 0 to 1000\n", $n); } $n++; }
http://rosettacode.org/wiki/Reduced_row_echelon_form	Reduced row echelon form	Reduced row echelon form You are encouraged to solve this task according to the task description, using any language you may know. Task Show how to compute the reduced row echelon form (a.k.a. row canonical form) of a matrix. The matrix can be stored in any datatype that is convenient (for most languages, this will probably be a two-dimensional array). Built-in functions or this pseudocode (from Wikipedia) may be used: function ToReducedRowEchelonForm(Matrix M) is lead := 0 rowCount := the number of rows in M columnCount := the number of columns in M for 0 ≤ r < rowCount do if columnCount ≤ lead then stop end if i = r while M[i, lead] = 0 do i = i + 1 if rowCount = i then i = r lead = lead + 1 if columnCount = lead then stop end if end if end while Swap rows i and r If M[r, lead] is not 0 divide row r by M[r, lead] for 0 ≤ i < rowCount do if i ≠ r do Subtract M[i, lead] multiplied by row r from row i end if end for lead = lead + 1 end for end function For testing purposes, the RREF of this matrix: 1 2 -1 -4 2 3 -1 -11 -2 0 -3 22 is: 1 0 0 -8 0 1 0 1 0 0 1 -2	#Icon_and_Unicon	Icon and Unicon	procedure main(A) tM := [[ 1, 2, -1, -4], [ 2, 3, -1,-11], [ -2, 0, -3, 22]] showMat(rref(tM)) end procedure rref(M) lead := 1 rCount := \M \| stop("no Matrix?") cCount := (M[1]) \| 0 every r := !rCount do { i := r while M[i,lead] = 0 do { if (i+:=1) > rCount then { i := r if cCount < (lead +:= 1) then stop("can't reduce") } } M[i] :=: M[r] if 0 ~= (m0 := M[r,lead]) then every !M[r] /:= real(m0) every r ~= (i := !rCount) do { every !(mr := copy(M[r])) *:= M[i,lead] every M[i,j := !cCount] -:= mr[j] } lead +:= 1 } return M end procedure showMat(M) every r := !M do every writes(right(!r,5)\|\|" " \| "\n") end
http://rosettacode.org/wiki/Real_constants_and_functions	Real constants and functions	Task Show how to use the following math constants and functions in your language (if not available, note it): e (base of the natural logarithm) π {\displaystyle \pi } square root logarithm (any base allowed) exponential (ex ) absolute value (a.k.a. "magnitude") floor (largest integer less than or equal to this number--not the same as truncate or int) ceiling (smallest integer not less than this number--not the same as round up) power (xy ) Related task Trigonometric Functions	#ERRE	ERRE	PROGRAM R_C_F FUNCTION CEILING(X) CEILING=INT(X)-(X-INT(X)>0) END FUNCTION FUNCTION FLOOR(X) FLOOR=INT(X) END FUNCTION BEGIN PRINT(EXP(1)) ! e not available PRINT(π) ! pi is available or .... PRINT(4*ATN(1)) ! .... equal to X=12.345 Y=1.23 PRINT(SQR(X),X^0.5) ! square root PRINT(LOG(X)) ! natural logarithm base e PRINT(LOG(X)/LOG(10)) ! base 10 logarithm PRINT(LOG(X)/LOG(Y)) ! arbitrary base logarithm (y>0) PRINT(EXP(X)) ! exponential PRINT(ABS(X)) ! absolute value PRINT(FLOOR(X)) ! floor PRINT(CEILING(X)) ! ceiling PRINT(X^Y) ! power END PROGRAM
http://rosettacode.org/wiki/Real_constants_and_functions	Real constants and functions	Task Show how to use the following math constants and functions in your language (if not available, note it): e (base of the natural logarithm) π {\displaystyle \pi } square root logarithm (any base allowed) exponential (ex ) absolute value (a.k.a. "magnitude") floor (largest integer less than or equal to this number--not the same as truncate or int) ceiling (smallest integer not less than this number--not the same as round up) power (xy ) Related task Trigonometric Functions	#F.23	F#	open System let main _ = Console.WriteLine(Math.E); // e Console.WriteLine(Math.PI); // Pi Console.WriteLine(Math.Sqrt(10.0)); // Square Root Console.WriteLine(Math.Log(10.0)); // Logarithm Console.WriteLine(Math.Log10(10.0)); // Base 10 Logarithm Console.WriteLine(Math.Exp(10.0)); // Exponential Console.WriteLine(Math.Abs(10)); // Absolute value Console.WriteLine(Math.Floor(10.0)); // Floor Console.WriteLine(Math.Ceiling(10.0)); // Ceiling Console.WriteLine(Math.Pow(2.0, 5.0)); // Exponentiation 0
http://rosettacode.org/wiki/Remove_lines_from_a_file	Remove lines from a file	Task Remove a specific line or a number of lines from a file. This should be implemented as a routine that takes three parameters (filename, starting line, and the number of lines to be removed). For the purpose of this task, line numbers and the number of lines start at one, so to remove the first two lines from the file foobar.txt, the parameters should be: foobar.txt, 1, 2 Empty lines are considered and should still be counted, and if the specified line is empty, it should still be removed. An appropriate message should appear if an attempt is made to remove lines beyond the end of the file.	#Mathematica.2FWolfram_Language	Mathematica/Wolfram Language	f[doc_String, start_Integer, n_Integer] := Module[{p, newdoc}, p = Import[doc, "List"]; If[start + n - 1 <= Length@p, p = Drop[p, {start, start + n - 1}]; newdoc = FileNameJoin[{DirectoryName[doc], FileBaseName[doc] <> "_removed.txt"}]; Export[newdoc, p, "List"]; , Print["Too few lines in document. Operation aborted."] ] ]
http://rosettacode.org/wiki/Remove_lines_from_a_file	Remove lines from a file	Task Remove a specific line or a number of lines from a file. This should be implemented as a routine that takes three parameters (filename, starting line, and the number of lines to be removed). For the purpose of this task, line numbers and the number of lines start at one, so to remove the first two lines from the file foobar.txt, the parameters should be: foobar.txt, 1, 2 Empty lines are considered and should still be counted, and if the specified line is empty, it should still be removed. An appropriate message should appear if an attempt is made to remove lines beyond the end of the file.	#NewLISP	NewLISP	(context 'ABC) (define (remove-lines-from-a-file filename start num) (setf new-content "") (setf row-counter 0) (setf start-delete-row start) (setf end-delete-row (+ start num -1)) (setf file-content (read-file filename)) (setf max-rows (length (parse file-content "\n" 0))) (cond ((<= start 0) (println "Start line must be >= 1. Value passed: " start)) ((<= num 0) (println "# of lines to remove must be >= 1. Value passed: " num)) ((> start max-rows) (println "Start line must be <= " max-rows ". Value passed: " start)) ((> end-delete-row max-rows) (println "Not so much lines available to be removed. Max " (- max-rows start-delete-row) ". Value passed: " num)) (true (dolist (row (parse file-content "\n" 0)) (++ row-counter) (if (or (< row-counter start-delete-row) (> row-counter end-delete-row)) (setf new-content (append new-content row "\n")) ) ) (write-file filename new-content) ) ) ) (context 'MAIN) (ABC:remove-lines-from-a-file "foobar.txt" 8 3) (exit)
http://rosettacode.org/wiki/Read_entire_file	Read entire file	Task Load the entire contents of some text file as a single string variable. If applicable, discuss: encoding selection, the possibility of memory-mapping. Of course, in practice one should avoid reading an entire file at once if the file is large and the task can be accomplished incrementally instead (in which case check File IO); this is for those cases where having the entire file is actually what is wanted.	#GAP	GAP	InputTextFile("input.txt"); s := ReadAll(f);; # two semicolons to hide the result, which may be long CloseStream(f);
http://rosettacode.org/wiki/Read_entire_file	Read entire file	Task Load the entire contents of some text file as a single string variable. If applicable, discuss: encoding selection, the possibility of memory-mapping. Of course, in practice one should avoid reading an entire file at once if the file is large and the task can be accomplished incrementally instead (in which case check File IO); this is for those cases where having the entire file is actually what is wanted.	#Genie	Genie	[indent=4] /* Read entire file, in Genie valac readEntireFile.gs ./readEntireFile [filename] */ init fileName:string fileContents:string fileName = (args[1] is null) ? "readEntireFile.gs" : args[1] try FileUtils.get_contents(fileName, out fileContents) except exc:Error print "Error: %s", exc.message return stdout.printf("%d bytes read from %s\n", fileContents.length, fileName)
http://rosettacode.org/wiki/Rep-string	Rep-string	Given a series of ones and zeroes in a string, define a repeated string or rep-string as a string which is created by repeating a substring of the first N characters of the string truncated on the right to the length of the input string, and in which the substring appears repeated at least twice in the original. For example, the string 10011001100 is a rep-string as the leftmost four characters of 1001 are repeated three times and truncated on the right to give the original string. Note that the requirement for having the repeat occur two or more times means that the repeating unit is never longer than half the length of the input string. Task Write a function/subroutine/method/... that takes a string and returns an indication of if it is a rep-string and the repeated string. (Either the string that is repeated, or the number of repeated characters would suffice). There may be multiple sub-strings that make a string a rep-string - in that case an indication of all, or the longest, or the shortest would suffice. Use the function to indicate the repeating substring if any, in the following: 1001110011 1110111011 0010010010 1010101010 1111111111 0100101101 0100100 101 11 00 1 Show your output on this page. Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet	#Phixmonti	Phixmonti	include ..\Utilitys.pmt def repstr /# s n -- s #/ "" swap for drop over chain endfor nip enddef def repString /# s -- s #/ len dup var sz 2 / 1 swap 2 tolist for var i 1 i slice var chunk chunk sz i / 1 + repstr 1 sz slice nip over == if chunk exitfor endif endfor len sz == sz 1 == or if ": No repeat string" chain else ": " swap chain chain endif enddef ( "1001110011" "1110111011" "0010010010" "1010101010" "1111111111" "0100101101" "0100100" "101" "11" "00" "1" ) len for get repString print nl endfor
http://rosettacode.org/wiki/Rep-string	Rep-string	Given a series of ones and zeroes in a string, define a repeated string or rep-string as a string which is created by repeating a substring of the first N characters of the string truncated on the right to the length of the input string, and in which the substring appears repeated at least twice in the original. For example, the string 10011001100 is a rep-string as the leftmost four characters of 1001 are repeated three times and truncated on the right to give the original string. Note that the requirement for having the repeat occur two or more times means that the repeating unit is never longer than half the length of the input string. Task Write a function/subroutine/method/... that takes a string and returns an indication of if it is a rep-string and the repeated string. (Either the string that is repeated, or the number of repeated characters would suffice). There may be multiple sub-strings that make a string a rep-string - in that case an indication of all, or the longest, or the shortest would suffice. Use the function to indicate the repeating substring if any, in the following: 1001110011 1110111011 0010010010 1010101010 1111111111 0100101101 0100100 101 11 00 1 Show your output on this page. Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet	#Picat	Picat	go => Strings = [ "1001110011", % 10011 "1110111011", % 1110 "0010010010", % 001 "1010101010", % 1010 "1111111111", % 11111 "0100101101", % no solution "0100100", % 010 "101", % no solution "11", % 1 "00", % 0 "1", % no solution "", % no solution "123123123123123", % 123123 "12312312312312", % 123123 "123123123123124", % no solution "abcabcdabcabcdabc", % abcabcd [1,2,3,4,1,2,3,4,1,2,3] % 1,2,3,4 ], foreach(S in Strings) printf("%w: ", S), if maxrep(S,Substr,N) then println([substr=Substr,n=N]) else println("no solution") end end, nl. % the largest repeating substring maxrep(S,Substr,N) => maxof(rep(S,Substr,N),N). rep(S,Substr,N) => between(1,S.length div 2, N), Len = S.length, Len2 = Len - (Len mod N), Substr = slice(S,1,N), % count the number of proper slices SS = [1 : I in 1..N..Len2, slice(S,I,I+N-1) = Substr], SS.length = Len div N, % the last (truncated) slice (or []) must be a substring of Substr Rest = slice(S,Len2+1,Len), find(Substr,Rest,1,_).
http://rosettacode.org/wiki/Regular_expressions	Regular expressions	Task match a string against a regular expression substitute part of a string using a regular expression	#ooRexx	ooRexx	/* Rexx / / Using the RxRegExp Regular Expression built-in utility class */ st1 = 'Fee, fie, foe, fum, I smell the blood of an Englishman' rx1 = '[Ff]?e' -- unlike most regex engines, RxRegExp uses '?' instead of '.' to match any single character sbx = 'foo' myRE = .RegularExpression~new() myRE~parse(rx1, MINIMAL) mcm = myRE~pos(st1) say 'String "'st1'"' 'matches pattern "'rx1'":' bool2string(mcm > 0) say -- The RxRegExp package doesn't provide a replace capability so you must roll your own st0 = st1 loop label GREP forever mcp = myRE~pos(st1) if mcp > 0 then do mpp = myRE~position fnd = st1~substr(mcp, mpp - mcp + 1) stx = st1~changestr(fnd, sbx, 1) end else leave GREP st1 = stx end GREP say 'Input string: "'st0'"' say 'Result string: "'stx'"' return exit bool2string: procedure do parse arg bv . if bv then bx = 'true' else bx = 'false' return bx end exit ::requires "rxregexp.cls"
http://rosettacode.org/wiki/Reverse_a_string	Reverse a string	Task Take a string and reverse it. For example, "asdf" becomes "fdsa". Extra credit Preserve Unicode combining characters. For example, "as⃝df̅" becomes "f̅ds⃝a", not "̅fd⃝sa". Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet	#COBOL	COBOL	FUNCTION REVERSE('QWERTY')
http://rosettacode.org/wiki/Repeat	Repeat	Task Write a procedure which accepts as arguments another procedure and a positive integer. The latter procedure is executed a number of times equal to the accepted integer.	#Tcl	Tcl	proc repeat {command count} { for {set i 0} {$i < $count} {incr i} { uplevel 1 $command } } proc example {} {puts "This is an example"} repeat example 4
http://rosettacode.org/wiki/Repeat	Repeat	Task Write a procedure which accepts as arguments another procedure and a positive integer. The latter procedure is executed a number of times equal to the accepted integer.	#uBasic.2F4tH	uBasic/4tH	Proc _Repeat (_HelloWorld, 5) : End _Repeat Param (2) : Local (1) : For c@ = 1 To b@ : Proc a@ : Next : Return _HelloWorld Print "Hello world!" : Return
http://rosettacode.org/wiki/Rename_a_file	Rename a file	Task Rename: a file called input.txt into output.txt and a directory called docs into mydocs. This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root. It can be assumed that the user has the rights to do so. (In unix-type systems, only the user root would have sufficient permissions in the filesystem root.)	#Pop11	Pop11	sys_file_move('inputs.txt', 'output.txt'); sys_file_move('docs', 'mydocs'); sys_file_move('/inputs.txt', '/output.txt'); sys_file_move(/'docs', '/mydocs');
http://rosettacode.org/wiki/Rename_a_file	Rename a file	Task Rename: a file called input.txt into output.txt and a directory called docs into mydocs. This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root. It can be assumed that the user has the rights to do so. (In unix-type systems, only the user root would have sufficient permissions in the filesystem root.)	#PowerShell	PowerShell	Rename-Item input.txt output.txt # The Rename-item has the alias ren ren input.txt output.txt
http://rosettacode.org/wiki/Reverse_words_in_a_string	Reverse words in a string	Task Reverse the order of all tokens in each of a number of strings and display the result; the order of characters within a token should not be modified. Example Hey you, Bub! would be shown reversed as: Bub! you, Hey Tokens are any non-space characters separated by spaces (formally, white-space); the visible punctuation form part of the word within which it is located and should not be modified. You may assume that there are no significant non-visible characters in the input. Multiple or superfluous spaces may be compressed into a single space. Some strings have no tokens, so an empty string (or one just containing spaces) would be the result. Display the strings in order (1st, 2nd, 3rd, ···), and one string per line. (You can consider the ten strings as ten lines, and the tokens as words.) Input data (ten lines within the box) line ╔════════════════════════════════════════╗ 1 ║ ---------- Ice and Fire ------------ ║ 2 ║ ║ ◄─── a blank line here. 3 ║ fire, in end will world the say Some ║ 4 ║ ice. in say Some ║ 5 ║ desire of tasted I've what From ║ 6 ║ fire. favor who those with hold I ║ 7 ║ ║ ◄─── a blank line here. 8 ║ ... elided paragraph last ... ║ 9 ║ ║ ◄─── a blank line here. 10 ║ Frost Robert ----------------------- ║ ╚════════════════════════════════════════╝ Cf. Phrase reversals	#Oforth	Oforth	: revWords(s) s words reverse unwords ; : reverseWords "---------- Ice and Fire ------------" revWords println " " revWords println "fire, in end will world the say Some" revWords println "ice. in say Some " revWords println "desire of tasted I've what From " revWords println "fire. favor who those with hold I " revWords println " " revWords println "... elided paragraph last ... " revWords println " " revWords println "Frost Robert -----------------------" revWords println ;
http://rosettacode.org/wiki/Reverse_words_in_a_string	Reverse words in a string	Task Reverse the order of all tokens in each of a number of strings and display the result; the order of characters within a token should not be modified. Example Hey you, Bub! would be shown reversed as: Bub! you, Hey Tokens are any non-space characters separated by spaces (formally, white-space); the visible punctuation form part of the word within which it is located and should not be modified. You may assume that there are no significant non-visible characters in the input. Multiple or superfluous spaces may be compressed into a single space. Some strings have no tokens, so an empty string (or one just containing spaces) would be the result. Display the strings in order (1st, 2nd, 3rd, ···), and one string per line. (You can consider the ten strings as ten lines, and the tokens as words.) Input data (ten lines within the box) line ╔════════════════════════════════════════╗ 1 ║ ---------- Ice and Fire ------------ ║ 2 ║ ║ ◄─── a blank line here. 3 ║ fire, in end will world the say Some ║ 4 ║ ice. in say Some ║ 5 ║ desire of tasted I've what From ║ 6 ║ fire. favor who those with hold I ║ 7 ║ ║ ◄─── a blank line here. 8 ║ ... elided paragraph last ... ║ 9 ║ ║ ◄─── a blank line here. 10 ║ Frost Robert ----------------------- ║ ╚════════════════════════════════════════╝ Cf. Phrase reversals	#Pascal	Pascal	program Reverse_words(Output); {$H+} const nl = chr(10); // Linefeed sp = chr(32); // Space TXT = '---------- Ice and Fire -----------'+nl+ nl+ 'fire, in end will world the say Some'+nl+ 'ice. in say Some'+nl+ 'desire of tasted I''ve what From'+nl+ 'fire. favor who those with hold I'+nl+ nl+ '... elided paragraph last ...'+nl+ nl+ 'Frost Robert -----------------------'+nl; var I : integer; ew, lw : ansistring; c : char; function addW : ansistring; var r : ansistring = ''; begin r := ew + sp + lw; ew := ''; addW := r end; begin ew := ''; lw := ''; for I := 1 to strlen(TXT) do begin c := TXT[I]; case c of sp : lw := addW; nl : begin writeln(addW); lw := '' end; else ew := ew + c end; end; readln; end.
http://rosettacode.org/wiki/Rot-13	Rot-13	Task Implement a rot-13 function (or procedure, class, subroutine, or other "callable" object as appropriate to your programming environment). Optionally wrap this function in a utility program (like tr, which acts like a common UNIX utility, performing a line-by-line rot-13 encoding of every line of input contained in each file listed on its command line, or (if no filenames are passed thereon) acting as a filter on its "standard input." (A number of UNIX scripting languages and utilities, such as awk and sed either default to processing files in this way or have command line switches or modules to easily implement these wrapper semantics, e.g., Perl and Python). The rot-13 encoding is commonly known from the early days of Usenet "Netnews" as a way of obfuscating text to prevent casual reading of spoiler or potentially offensive material. Many news reader and mail user agent programs have built-in rot-13 encoder/decoders or have the ability to feed a message through any external utility script for performing this (or other) actions. The definition of the rot-13 function is to simply replace every letter of the ASCII alphabet with the letter which is "rotated" 13 characters "around" the 26 letter alphabet from its normal cardinal position (wrapping around from z to a as necessary). Thus the letters abc become nop and so on. Technically rot-13 is a "mono-alphabetic substitution cipher" with a trivial "key". A proper implementation should work on upper and lower case letters, preserve case, and pass all non-alphabetic characters in the input stream through without alteration. Related tasks Caesar cipher Substitution Cipher Vigenère Cipher/Cryptanalysis Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet	#Smalltalk	Smalltalk	"1. simple approach" rot13 := [ :string \| string collect: [ :each \| \| index \| index := 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ' indexOf: each ifAbsent: [ 0 ]. "Smalltalk uses 1-based indexing" index isZero ifTrue: [ each ] ifFalse: [ 'nopqrstuvwxyzabcdefghijklmNOPQRSTUVWXYZABCDEFGHIJKLM' at: index ] ] ]. (rot13 value: 'Test123') printNl "gives 'Grfg123'" "2. extending built-in classes" Character extend [ + inc [ (inc isKindOf: Character) ifTrue: [ ^ ( Character value: ((self asInteger) + (inc asInteger)) ) ] ifFalse: [ ^ ( Character value: ((self asInteger) + inc) ) ] ] - inc [ ^ ( self + (inc asInteger negated) ) ] trFrom: map1 to: map2 [ (map1 includes: self) ifTrue: [ ^ map2 at: (map1 indexOf: self) ] ifFalse: [ ^self ] ] ]. String extend [ rot: num [ \|s\| s := String new. self do: [ :c \| ((c asLowercase) between: $a and: $z) ifTrue: [ \|c1\| c1 := ( $a + ((((c asLowercase) - $a + num) asInteger) rem:26)). (c isLowercase) ifFalse: [ c1 := c1 asUppercase ]. s := s, (c1 asString) ] ifFalse: [ s := s, (c asString) ] ]. ^s ] ]. ('abcdefghijklmnopqrstuvwxyz123!' rot: 13) displayNl. (('abcdefghijklmnopqrstuvwxyz123!' rot: 13) rot: 13) displayNl. "2. using a 'translation'. Not very idiomatic Smalltalk code" rotThirteen := [ :s \| \|m1 m2 r\| r := String new. m1 := OrderedCollection new. 0 to: 25 do: [ :i \| m1 add: ($a + i) ]. m2 := OrderedCollection new. 0 to: 25 do: [ :i \| m2 add: ($a + ((i+13) rem: 26)) ]. s do: [ :c \| (c between: $a and: $z) \| (c between: $A and: $Z) ifTrue: [ \| a \| a := (c asLowercase) trFrom: m1 to: m2. (c isUppercase) ifTrue: [ a := a asUppercase ]. r := r, (a asString)] ifFalse: [ r := r, (c asString) ] ]. r ]. (rotThirteen value: 'abcdefghijklmnopqrstuvwxyz123!') displayNl.
http://rosettacode.org/wiki/Roman_numerals/Encode	Roman numerals/Encode	Task Create a function taking a positive integer as its parameter and returning a string containing the Roman numeral representation of that integer. Modern Roman numerals are written by expressing each digit separately, starting with the left most digit and skipping any digit with a value of zero. In Roman numerals: 1990 is rendered: 1000=M, 900=CM, 90=XC; resulting in MCMXC 2008 is written as 2000=MM, 8=VIII; or MMVIII 1666 uses each Roman symbol in descending order: MDCLXVI	#Shen	Shen	(define encodeGlyphs ACC 0 _ -> ACC ACC N [Glyph Value \| Rest] -> (encodeGlyphs (@s ACC Glyph) (- N Value) [Glyph Value \| Rest]) where (>= N Value) ACC N [Glyph Value \| Rest] -> (encodeGlyphs ACC N Rest) ) (define encodeRoman N -> (encodeGlyphs "" N ["M" 1000 "CM" 900 "D" 500 "CD" 400 "C" 100 "XC" 90 "L" 50 "XL" 40 "X" 10 "IX" 9 "V" 5 "IV" 4 "I" 1]) )
http://rosettacode.org/wiki/Roman_numerals/Decode	Roman numerals/Decode	Task Create a function that takes a Roman numeral as its argument and returns its value as a numeric decimal integer. You don't need to validate the form of the Roman numeral. Modern Roman numerals are written by expressing each decimal digit of the number to be encoded separately, starting with the leftmost decimal digit and skipping any 0s (zeroes). 1990 is rendered as MCMXC (1000 = M, 900 = CM, 90 = XC) and 2008 is rendered as MMVIII (2000 = MM, 8 = VIII). The Roman numeral for 1666, MDCLXVI, uses each letter in descending order.	#Yabasic	Yabasic	romans$ = "MDCLXVI" decmls$ = "1000,500,100,50,10,5,1" sub romanDec(s$) local i, n, prev, res, decmls$(1) n = token(decmls$, decmls$(), ",") for i = len(s$) to 1 step -1 n = val(decmls$(instr(romans$, mid$(s$, i, 1)))) if n < prev n = 0 - n res = res + n prev = n next i return res end sub ? romanDec("MCMXCIX") // 1999 ? romanDec("MDCLXVI") // 1666 ? romanDec("XXV") // 25 ? romanDec("XIX") // 19 ? romanDec("XI") // 11 ? romanDec("CMLIV") // 954 ? romanDec("MMXI") // 2011 ? romanDec("CD") // 400 ? romanDec("MCMXC") // 1990 ? romanDec("MMVIII") // 2008 ? romanDec("MMIX") // 2009 ? romanDec("MDCLXVI") // 1666 ? romanDec("MMMDCCCLXXXVIII") // 3888
http://rosettacode.org/wiki/Repeat_a_string	Repeat a string	Take a string and repeat it some number of times. Example: repeat("ha", 5) => "hahahahaha" If there is a simpler/more efficient way to repeat a single “character” (i.e. creating a string filled with a certain character), you might want to show that as well (i.e. repeat-char("", 5) => "****"). Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet	#Gambas	Gambas	Public Sub Main() Print String$(5, "ha") End
http://rosettacode.org/wiki/Return_multiple_values	Return multiple values	Task Show how to return more than one value from a function.	#PL.2FI	PL/I	define structure 1 h, 2 a (10) float; declare i fixed binary; sub: procedure (a, b) returns (type(h)); declare (a, b) float; declare p type (h); do i = 1 to 10; p.a(i) = i; end; return (p); end sub;
http://rosettacode.org/wiki/Return_multiple_values	Return multiple values	Task Show how to return more than one value from a function.	#Plain_English	Plain English	To run: Start up. Compute a product and a quotient given 15 and 3. Write "The product is " then the product on the console. Write "The quotient is " then the quotient on the console. Wait for the escape key. Shut down. A product is a number. To compute a product and a quotient given a number and another number: Put the number times the other number into the product. Put the number divided by the other number into the quotient.
http://rosettacode.org/wiki/Remove_duplicate_elements	Remove duplicate elements	Sorting Algorithm This is a sorting algorithm. It may be applied to a set of data in order to sort it. For comparing various sorts, see compare sorts. For other sorting algorithms, see sorting algorithms, or: O(n logn) sorts Heap sort \| Merge sort \| Patience sort \| Quick sort O(n log2n) sorts Shell Sort O(n2) sorts Bubble sort \| Cocktail sort \| Cocktail sort with shifting bounds \| Comb sort \| Cycle sort \| Gnome sort \| Insertion sort \| Selection sort \| Strand sort other sorts Bead sort \| Bogo sort \| Common sorted list \| Composite structures sort \| Custom comparator sort \| Counting sort \| Disjoint sublist sort \| External sort \| Jort sort \| Lexicographical sort \| Natural sorting \| Order by pair comparisons \| Order disjoint list items \| Order two numerical lists \| Object identifier (OID) sort \| Pancake sort \| Quickselect \| Permutation sort \| Radix sort \| Ranking methods \| Remove duplicate elements \| Sleep sort \| Stooge sort \| [Sort letters of a string] \| Three variable sort \| Topological sort \| Tree sort Given an Array, derive a sequence of elements in which all duplicates are removed. There are basically three approaches seen here: Put the elements into a hash table which does not allow duplicates. The complexity is O(n) on average, and O(n2) worst case. This approach requires a hash function for your type (which is compatible with equality), either built-in to your language, or provided by the user. Sort the elements and remove consecutive duplicate elements. The complexity of the best sorting algorithms is O(n log n). This approach requires that your type be "comparable", i.e., have an ordering. Putting the elements into a self-balancing binary search tree is a special case of sorting. Go through the list, and for each element, check the rest of the list to see if it appears again, and discard it if it does. The complexity is O(n2). The up-shot is that this always works on any type (provided that you can test for equality).	#Euphoria	Euphoria	include sort.e function uniq(sequence s) sequence out s = sort(s) out = s[1..1] for i = 2 to length(s) do if not equal(s[i],out[$]) then out = append(out, s[i]) end if end for return out end function constant s = {1, 2, 1, 4, 5, 2, 15, 1, 3, 4} ? s ? uniq(s)
http://rosettacode.org/wiki/Recaman%27s_sequence	Recaman's sequence	The Recamán's sequence generates Natural numbers. Starting from a(0)=0, the n'th term a(n), where n>0, is the previous term minus n i.e a(n) = a(n-1) - n but only if this is both positive and has not been previousely generated. If the conditions don't hold then a(n) = a(n-1) + n. Task Generate and show here the first 15 members of the sequence. Find and show here, the first duplicated number in the sequence. Optionally: Find and show here, how many terms of the sequence are needed until all the integers 0..1000, inclusive, are generated. References A005132, The On-Line Encyclopedia of Integer Sequences. The Slightly Spooky Recamán Sequence, Numberphile video. Recamán's sequence, on Wikipedia.	#PL.2FI	PL/I	recaman: procedure options(main); declare A(0:30) fixed; /* is X in the first N terms of the Recaman sequence? / find: procedure(x, n) returns(bit); declare (x, n, i) fixed; do i=0 to n-1; if A(i)=x then return('1'b); end; return('0'b); end find; / generate the N'th term of the Recaman sequence / generate: procedure(n) returns(fixed); declare n fixed; if n=0 then A(0) = 0; else do; declare (sub, add) fixed; sub = A(n-1) - n; add = A(n-1) + n; / A(n-1) - n not positive? / if sub <= 0 then A(n) = add; / A(n-1) - n already generated? */ else if find(sub, n) then A(n) = add; else A(n) = sub; end; return(A(n)); end generate; declare i fixed; put skip list('First 15 members:'); do i=0 to 14; put edit(generate(i)) (F(3)); end; put skip list('First repeated term: '); do i=15 repeat(i+1) while(^find(generate(i), i)); end; put edit('A(',i,') = ',A(i)) (A,F(2),A,F(2)); end recaman;
http://rosettacode.org/wiki/Reduced_row_echelon_form	Reduced row echelon form	Reduced row echelon form You are encouraged to solve this task according to the task description, using any language you may know. Task Show how to compute the reduced row echelon form (a.k.a. row canonical form) of a matrix. The matrix can be stored in any datatype that is convenient (for most languages, this will probably be a two-dimensional array). Built-in functions or this pseudocode (from Wikipedia) may be used: function ToReducedRowEchelonForm(Matrix M) is lead := 0 rowCount := the number of rows in M columnCount := the number of columns in M for 0 ≤ r < rowCount do if columnCount ≤ lead then stop end if i = r while M[i, lead] = 0 do i = i + 1 if rowCount = i then i = r lead = lead + 1 if columnCount = lead then stop end if end if end while Swap rows i and r If M[r, lead] is not 0 divide row r by M[r, lead] for 0 ≤ i < rowCount do if i ≠ r do Subtract M[i, lead] multiplied by row r from row i end if end for lead = lead + 1 end for end function For testing purposes, the RREF of this matrix: 1 2 -1 -4 2 3 -1 -11 -2 0 -3 22 is: 1 0 0 -8 0 1 0 1 0 0 1 -2	#J	J	NB.pivot v Pivot at row, column NB. form: (row,col) pivot M pivot=: dyad define 'r c'=. x col=. c{"1 y y - (col - r = i.#y) / (r{y) % r{col ) NB.gauss_jordan v Gauss-Jordan elimination (full pivoting) NB. y is: matrix NB. x is: optional minimum tolerance, default 1e_15. NB. If a column below the current pivot has numbers of magnitude all NB. less then x, it is treated as all zeros. gauss_jordan=: verb define 1e_15 gauss_jordan y : mtx=. y 'r c'=. $mtx rows=. i.r i=. j=. 0 max=. i.>./ while. (i<r) . j<c do. k=. max col=. \| i}. j{"1 mtx if. 0 < x-k{col do. NB. if all col < tol, set to 0: mtx=. 0 (<(i}.rows);j) } mtx else. NB. otherwise sort and pivot: if. k do. mtx=. (<i,i+k) C. mtx end. mtx=. (i,j) pivot mtx i=. >:i end. j=. >:j end. mtx )
http://rosettacode.org/wiki/Real_constants_and_functions	Real constants and functions	Task Show how to use the following math constants and functions in your language (if not available, note it): e (base of the natural logarithm) π {\displaystyle \pi } square root logarithm (any base allowed) exponential (ex ) absolute value (a.k.a. "magnitude") floor (largest integer less than or equal to this number--not the same as truncate or int) ceiling (smallest integer not less than this number--not the same as round up) power (xy ) Related task Trigonometric Functions	#Factor	Factor	e ! e pi ! π sqrt ! square root log ! natural logarithm exp ! exponentiation abs ! absolute value floor ! greatest whole number smaller than or equal ceiling ! smallest whole number greater than or equal truncate ! remove the fractional part (i.e. round towards 0) round ! round to next whole number ^ ! power
http://rosettacode.org/wiki/Real_constants_and_functions	Real constants and functions	Task Show how to use the following math constants and functions in your language (if not available, note it): e (base of the natural logarithm) π {\displaystyle \pi } square root logarithm (any base allowed) exponential (ex ) absolute value (a.k.a. "magnitude") floor (largest integer less than or equal to this number--not the same as truncate or int) ceiling (smallest integer not less than this number--not the same as round up) power (xy ) Related task Trigonometric Functions	#Fantom	Fantom	Float.e Float.pi 9f.sqrt 9f.log // natural logarithm 9f.log10 // logarithm to base 10 9f.exp // exponentiation (-3f).abs // absolute value, note bracket 3.2f.floor // nearest Int smaller than this number 3.2f.ceil // nearest Int bigger than this number 3.2f.round // nearest Int 3f.pow(2f) // power
http://rosettacode.org/wiki/Remove_lines_from_a_file	Remove lines from a file	Task Remove a specific line or a number of lines from a file. This should be implemented as a routine that takes three parameters (filename, starting line, and the number of lines to be removed). For the purpose of this task, line numbers and the number of lines start at one, so to remove the first two lines from the file foobar.txt, the parameters should be: foobar.txt, 1, 2 Empty lines are considered and should still be counted, and if the specified line is empty, it should still be removed. An appropriate message should appear if an attempt is made to remove lines beyond the end of the file.	#Nim	Nim	import sequtils, strutils proc removeLines*(filename: string; start, count: Positive) = # Read the whole file, split into lines but keep the ends of line. var lines = filename.readFile().splitLines(keepEol = true) # Remove final empty string if any. if lines[^1].len == 0: lines.setLen(lines.len - 1) # Compute indices and check validity. let first = start - 1 let last = first + count - 1 if last >= lines.len: raise newException(IOError, "trying to delete lines after end of file.") # Delete the lines and write the file. lines.delete(first, last) filename.writeFile(lines.join())
http://rosettacode.org/wiki/Remove_lines_from_a_file	Remove lines from a file	Task Remove a specific line or a number of lines from a file. This should be implemented as a routine that takes three parameters (filename, starting line, and the number of lines to be removed). For the purpose of this task, line numbers and the number of lines start at one, so to remove the first two lines from the file foobar.txt, the parameters should be: foobar.txt, 1, 2 Empty lines are considered and should still be counted, and if the specified line is empty, it should still be removed. An appropriate message should appear if an attempt is made to remove lines beyond the end of the file.	#OCaml	OCaml	let input_line_opt ic = try Some (input_line ic) with End_of_file -> None let delete_lines filename start skip = if start < 1 \|\| skip < 1 then invalid_arg "delete_lines"; let tmp_file = filename ^ ".tmp" in let ic = open_in filename and oc = open_out tmp_file in let until = start + skip - 1 in let rec aux i = match input_line_opt ic with \| Some line -> if i < start \|\| i > until then (output_string oc line; output_char oc '\n'); aux (succ i) \| None -> close_in ic; close_out oc; Sys.remove filename; Sys.rename tmp_file filename in aux 1 let usage () = Printf.printf "Usage:\n%s <filename> <startline> <skipnumber>\n" Sys.argv.(0); exit 0 let () = if Array.length Sys.argv < 4 then usage (); delete_lines Sys.argv.(1) (int_of_string Sys.argv.(2)) (int_of_string Sys.argv.(3))
http://rosettacode.org/wiki/Read_entire_file	Read entire file	Task Load the entire contents of some text file as a single string variable. If applicable, discuss: encoding selection, the possibility of memory-mapping. Of course, in practice one should avoid reading an entire file at once if the file is large and the task can be accomplished incrementally instead (in which case check File IO); this is for those cases where having the entire file is actually what is wanted.	#Go	Go	import "io/ioutil" data, err := ioutil.ReadFile(filename) sv := string(data)
http://rosettacode.org/wiki/Read_entire_file	Read entire file	Task Load the entire contents of some text file as a single string variable. If applicable, discuss: encoding selection, the possibility of memory-mapping. Of course, in practice one should avoid reading an entire file at once if the file is large and the task can be accomplished incrementally instead (in which case check File IO); this is for those cases where having the entire file is actually what is wanted.	#Groovy	Groovy	def fileContent = new File("c:\\file.txt").text
http://rosettacode.org/wiki/Rep-string	Rep-string	Given a series of ones and zeroes in a string, define a repeated string or rep-string as a string which is created by repeating a substring of the first N characters of the string truncated on the right to the length of the input string, and in which the substring appears repeated at least twice in the original. For example, the string 10011001100 is a rep-string as the leftmost four characters of 1001 are repeated three times and truncated on the right to give the original string. Note that the requirement for having the repeat occur two or more times means that the repeating unit is never longer than half the length of the input string. Task Write a function/subroutine/method/... that takes a string and returns an indication of if it is a rep-string and the repeated string. (Either the string that is repeated, or the number of repeated characters would suffice). There may be multiple sub-strings that make a string a rep-string - in that case an indication of all, or the longest, or the shortest would suffice. Use the function to indicate the repeating substring if any, in the following: 1001110011 1110111011 0010010010 1010101010 1111111111 0100101101 0100100 101 11 00 1 Show your output on this page. Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet	#PicoLisp	PicoLisp	(de repString (Str) (let Lst (chop Str) (for (N (/ (length Lst) 2) (gt0 N) (dec N)) (T (use (Lst X) (let H (cut N 'Lst) (loop (setq X (cut N 'Lst)) (NIL (head X H)) (NIL Lst T) ) ) ) N ) ) ) )
http://rosettacode.org/wiki/Rep-string	Rep-string	Given a series of ones and zeroes in a string, define a repeated string or rep-string as a string which is created by repeating a substring of the first N characters of the string truncated on the right to the length of the input string, and in which the substring appears repeated at least twice in the original. For example, the string 10011001100 is a rep-string as the leftmost four characters of 1001 are repeated three times and truncated on the right to give the original string. Note that the requirement for having the repeat occur two or more times means that the repeating unit is never longer than half the length of the input string. Task Write a function/subroutine/method/... that takes a string and returns an indication of if it is a rep-string and the repeated string. (Either the string that is repeated, or the number of repeated characters would suffice). There may be multiple sub-strings that make a string a rep-string - in that case an indication of all, or the longest, or the shortest would suffice. Use the function to indicate the repeating substring if any, in the following: 1001110011 1110111011 0010010010 1010101010 1111111111 0100101101 0100100 101 11 00 1 Show your output on this page. Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet	#PL.2FI	PL/I	rep: procedure options (main); /* 5 May 2015 */ declare s bit (10) varying; declare (i, k) fixed binary; main_loop: do s = '1001110011'b, '1110111011'b, '0010010010'b, '1010101010'b, '1111111111'b, '0100101101'b, '0100100'b, '101'b, '11'b, '00'b, '1'b; k = length(s); do i = k/2 to 1 by -1; if substr(s, 1, i) = substr(s, i+1, i) then do; put skip edit (s, ' is a rep-string containing ', substr(s, 1, i) ) (a); iterate main_loop; end; end; put skip edit (s, ' is not a rep-string') (a); end; end rep;
http://rosettacode.org/wiki/Regular_expressions	Regular expressions	Task match a string against a regular expression substitute part of a string using a regular expression	#Oxygene	Oxygene	// Match and Replace part of a string using a Regular Expression // // Nigel Galloway - April 15th., 2012 // namespace re; interface type re = class public class method Main; end; implementation class method re.Main; const myString = 'I think that I am Nigel'; var r: System.Text.RegularExpressions.Regex; myResult : String; begin r := new System.Text.RegularExpressions.Regex('(I am)\|(you are)'); Console.WriteLine("{0} contains {1}", myString, r.Match(myString)); myResult := r.Replace(myString, "you are"); Console.WriteLine("{0} contains {1}", myResult, r.Match(myResult)); end; end.
http://rosettacode.org/wiki/Reverse_a_string	Reverse a string	Task Take a string and reverse it. For example, "asdf" becomes "fdsa". Extra credit Preserve Unicode combining characters. For example, "as⃝df̅" becomes "f̅ds⃝a", not "̅fd⃝sa". Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet	#CoffeeScript	CoffeeScript	"qwerty".split("").reverse().join ""
http://rosettacode.org/wiki/Repeat	Repeat	Task Write a procedure which accepts as arguments another procedure and a positive integer. The latter procedure is executed a number of times equal to the accepted integer.	#Ursa	Ursa	def repeat (function f, int n) for (set n n) (> n 0) (dec n) f end for end repeat def procedure () out "Hello! " console end procedure # outputs "Hello! " 5 times repeat procedure 5
http://rosettacode.org/wiki/Repeat	Repeat	Task Write a procedure which accepts as arguments another procedure and a positive integer. The latter procedure is executed a number of times equal to the accepted integer.	#VBA	VBA	Private Sub Repeat(rid As String, n As Integer) For i = 1 To n Application.Run rid Next i End Sub Private Sub Hello() Debug.Print "Hello" End Sub Public Sub main() Repeat "Hello", 5 End Sub
http://rosettacode.org/wiki/Rename_a_file	Rename a file	Task Rename: a file called input.txt into output.txt and a directory called docs into mydocs. This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root. It can be assumed that the user has the rights to do so. (In unix-type systems, only the user root would have sufficient permissions in the filesystem root.)	#Processing	Processing	void setup(){ boolean sketchfile = rename(sketchPath("input.txt"), sketchPath("output.txt")); boolean sketchfold = rename(sketchPath("docs"), sketchPath("mydocs")); // sketches will seldom have write permission to root files/folders boolean rootfile = rename("input.txt", "output.txt"); boolean rootfold = rename("docs", "mydocs"); // true if succeeded, false if failed println(sketchfile, sketchfold, rootfile, rootfold); } boolean rename(String oldname, String newname) { // File (or directory) with old name File file = new File(oldname); // File (or directory) with new name File file2 = new File(newname); // Rename file (or directory) boolean success = file.renameTo(file2); return success; }
http://rosettacode.org/wiki/Rename_a_file	Rename a file	Task Rename: a file called input.txt into output.txt and a directory called docs into mydocs. This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root. It can be assumed that the user has the rights to do so. (In unix-type systems, only the user root would have sufficient permissions in the filesystem root.)	#ProDOS	ProDOS	rename input.txt to output.txt rename docs to mydocs
http://rosettacode.org/wiki/Reverse_words_in_a_string	Reverse words in a string	Task Reverse the order of all tokens in each of a number of strings and display the result; the order of characters within a token should not be modified. Example Hey you, Bub! would be shown reversed as: Bub! you, Hey Tokens are any non-space characters separated by spaces (formally, white-space); the visible punctuation form part of the word within which it is located and should not be modified. You may assume that there are no significant non-visible characters in the input. Multiple or superfluous spaces may be compressed into a single space. Some strings have no tokens, so an empty string (or one just containing spaces) would be the result. Display the strings in order (1st, 2nd, 3rd, ···), and one string per line. (You can consider the ten strings as ten lines, and the tokens as words.) Input data (ten lines within the box) line ╔════════════════════════════════════════╗ 1 ║ ---------- Ice and Fire ------------ ║ 2 ║ ║ ◄─── a blank line here. 3 ║ fire, in end will world the say Some ║ 4 ║ ice. in say Some ║ 5 ║ desire of tasted I've what From ║ 6 ║ fire. favor who those with hold I ║ 7 ║ ║ ◄─── a blank line here. 8 ║ ... elided paragraph last ... ║ 9 ║ ║ ◄─── a blank line here. 10 ║ Frost Robert ----------------------- ║ ╚════════════════════════════════════════╝ Cf. Phrase reversals	#Perl	Perl	print join(" ", reverse split), "\n" for <DATA>; __DATA__ ---------- Ice and Fire ------------ fire, in end will world the say Some ice. in say Some desire of tasted I've what From fire. favor who those with hold I ... elided paragraph last ... Frost Robert -----------------------
http://rosettacode.org/wiki/Reverse_words_in_a_string	Reverse words in a string	Task Reverse the order of all tokens in each of a number of strings and display the result; the order of characters within a token should not be modified. Example Hey you, Bub! would be shown reversed as: Bub! you, Hey Tokens are any non-space characters separated by spaces (formally, white-space); the visible punctuation form part of the word within which it is located and should not be modified. You may assume that there are no significant non-visible characters in the input. Multiple or superfluous spaces may be compressed into a single space. Some strings have no tokens, so an empty string (or one just containing spaces) would be the result. Display the strings in order (1st, 2nd, 3rd, ···), and one string per line. (You can consider the ten strings as ten lines, and the tokens as words.) Input data (ten lines within the box) line ╔════════════════════════════════════════╗ 1 ║ ---------- Ice and Fire ------------ ║ 2 ║ ║ ◄─── a blank line here. 3 ║ fire, in end will world the say Some ║ 4 ║ ice. in say Some ║ 5 ║ desire of tasted I've what From ║ 6 ║ fire. favor who those with hold I ║ 7 ║ ║ ◄─── a blank line here. 8 ║ ... elided paragraph last ... ║ 9 ║ ║ ◄─── a blank line here. 10 ║ Frost Robert ----------------------- ║ ╚════════════════════════════════════════╝ Cf. Phrase reversals	#Phix	Phix	with javascript_semantics constant test=""" ---------- Ice and Fire ------------ fire, in end will world the say Some ice. in say Some desire of tasted I've what From fire. favor who those with hold I ... elided paragraph last ... Frost Robert ----------------------- """ sequence lines = split(test,'\n') for i=1 to length(lines) do lines[i] = join(reverse(split(lines[i]))) end for puts(1,join(lines,"\n"))
http://rosettacode.org/wiki/Rot-13	Rot-13	Task Implement a rot-13 function (or procedure, class, subroutine, or other "callable" object as appropriate to your programming environment). Optionally wrap this function in a utility program (like tr, which acts like a common UNIX utility, performing a line-by-line rot-13 encoding of every line of input contained in each file listed on its command line, or (if no filenames are passed thereon) acting as a filter on its "standard input." (A number of UNIX scripting languages and utilities, such as awk and sed either default to processing files in this way or have command line switches or modules to easily implement these wrapper semantics, e.g., Perl and Python). The rot-13 encoding is commonly known from the early days of Usenet "Netnews" as a way of obfuscating text to prevent casual reading of spoiler or potentially offensive material. Many news reader and mail user agent programs have built-in rot-13 encoder/decoders or have the ability to feed a message through any external utility script for performing this (or other) actions. The definition of the rot-13 function is to simply replace every letter of the ASCII alphabet with the letter which is "rotated" 13 characters "around" the 26 letter alphabet from its normal cardinal position (wrapping around from z to a as necessary). Thus the letters abc become nop and so on. Technically rot-13 is a "mono-alphabetic substitution cipher" with a trivial "key". A proper implementation should work on upper and lower case letters, preserve case, and pass all non-alphabetic characters in the input stream through without alteration. Related tasks Caesar cipher Substitution Cipher Vigenère Cipher/Cryptanalysis Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet	#SNOBOL4	SNOBOL4	* # Function using replace( ) define('rot13(s)u1,u2,l1,l2') :(rot13_end) rot13 &ucase len(13) . u1 rem . u2 &lcase len(13) . l1 rem . l2 rot13 = replace(s,&ucase &lcase,u2 u1 l2 l1) :(return) rot13_end * # Function using pattern define('rot13s(s)c') alfa = &ucase &ucase &lcase &lcase :(rot13s_end) rot13s s len(1) . c = :f(return) alfa break(c) len(13) len(1) . c rot13s = rot13s c :(rot13s) rot13s_end * # Test and display both str = rot13("I abjure the $19.99 trinket!") output = str; output = rot13(str) str = rot13s("He's a real Nowhere Man.") output = str; output = rot13s(str) end
http://rosettacode.org/wiki/Roman_numerals/Encode	Roman numerals/Encode	Task Create a function taking a positive integer as its parameter and returning a string containing the Roman numeral representation of that integer. Modern Roman numerals are written by expressing each digit separately, starting with the left most digit and skipping any digit with a value of zero. In Roman numerals: 1990 is rendered: 1000=M, 900=CM, 90=XC; resulting in MCMXC 2008 is written as 2000=MM, 8=VIII; or MMVIII 1666 uses each Roman symbol in descending order: MDCLXVI	#Sidef	Sidef	func arabic2roman(num, roman='') { static lookup = [ :M:1000, :CM:900, :D:500, :CD:400, :C:100, :XC:90, :L:50, :XL:40, :X:10, :IX:9, :V:5, :IV:4, :I:1 ]; lookup.each { \|pair\| while (num >= pair.second) { roman += pair.first; num -= pair.second; } } return roman; } say("1990 in roman is " + arabic2roman(1990)); say("2008 in roman is " + arabic2roman(2008)); say("1666 in roman is " + arabic2roman(1666));
http://rosettacode.org/wiki/Roman_numerals/Decode	Roman numerals/Decode	Task Create a function that takes a Roman numeral as its argument and returns its value as a numeric decimal integer. You don't need to validate the form of the Roman numeral. Modern Roman numerals are written by expressing each decimal digit of the number to be encoded separately, starting with the leftmost decimal digit and skipping any 0s (zeroes). 1990 is rendered as MCMXC (1000 = M, 900 = CM, 90 = XC) and 2008 is rendered as MMVIII (2000 = MM, 8 = VIII). The Roman numeral for 1666, MDCLXVI, uses each letter in descending order.	#zkl	zkl	var romans = L( L("M", 1000), L("CM", 900), L("D", 500), L("CD", 400), L("C", 100), L("XC", 90), L("L", 50), L("XL", 40), L("X", 10), L("IX", 9), L("V", 5), L("IV", 4), L("I", 1)); fcn toArabic(romanNumber){ // romanNumber needs to be upper case if (not RegExp("^[CDILMVX]+$").matches(romanNumber)) throw(Exception.ValueError("Not a Roman number: %s".fmt(romanNumber))); reg value = 0; foreach R,N in (romans){ while (0 == romanNumber.find(R)){ value += N; romanNumber = romanNumber[R.len(),*]; } } return(value); }
http://rosettacode.org/wiki/Repeat_a_string	Repeat a string	Take a string and repeat it some number of times. Example: repeat("ha", 5) => "hahahahaha" If there is a simpler/more efficient way to repeat a single “character” (i.e. creating a string filled with a certain character), you might want to show that as well (i.e. repeat-char("", 5) => "****"). Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet	#GAP	GAP	Concatenation(ListWithIdenticalEntries(10, "BOB ")); "BOB BOB BOB BOB BOB BOB BOB BOB BOB BOB "
http://rosettacode.org/wiki/Repeat_a_string	Repeat a string	Take a string and repeat it some number of times. Example: repeat("ha", 5) => "hahahahaha" If there is a simpler/more efficient way to repeat a single “character” (i.e. creating a string filled with a certain character), you might want to show that as well (i.e. repeat-char("", 5) => "****"). Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet	#Glee	Glee	'*' %% 5
http://rosettacode.org/wiki/Return_multiple_values	Return multiple values	Task Show how to return more than one value from a function.	#PowerShell	PowerShell	function multiple-value ($a, $b) { [pscustomobject]@{ a = $a b = $b } } $m = multiple-value "value" 1 $m.a $m.b
http://rosettacode.org/wiki/Return_multiple_values	Return multiple values	Task Show how to return more than one value from a function.	#PureBasic	PureBasic	;An array, map, or list can be used as a parameter to a procedure and in the ;process contain values to be returned as well. Procedure example_1(x, y, Array r(1)) ;array r() will contain the return values Dim r(2) ;clear and resize the array r(0) = x + y ;return these values in the array r(1) = x - y r(2) = x * y EndProcedure ;A pointer to memory or a structured variable may also be returned to reference ;multiple return values (requiring the memory to be manually freed afterwards). Procedure example_2(x, y) Protected result.POINT = AllocateMemory(SizeOf(POINT)) result\x = x result\y = y ProcedureReturn result ;result points to a 'POINT' structure containing x and y EndProcedure If OpenConsole() Dim a(5) example_1(6, 5, a()) ;a() now contains {11, 1, 30} PrintN("Array returned with {" + Str(a(0)) + ", " + Str(a(1)) + ", " + Str(a(2)) + "}") Define aPoint.POINT aPoint = example_2(6, 5) ;aPoint references structured memory containing {6, 5} PrintN("structured memory holds: (" + Str(aPoint\x) + ", " + Str(aPoint\y) + ")") FreeMemory(*aPoint) ;freememory Print(#CRLF$ + #CRLF$ + "Press ENTER to exit"): Input() CloseConsole() EndIf
http://rosettacode.org/wiki/Remove_duplicate_elements	Remove duplicate elements	Sorting Algorithm This is a sorting algorithm. It may be applied to a set of data in order to sort it. For comparing various sorts, see compare sorts. For other sorting algorithms, see sorting algorithms, or: O(n logn) sorts Heap sort \| Merge sort \| Patience sort \| Quick sort O(n log2n) sorts Shell Sort O(n2) sorts Bubble sort \| Cocktail sort \| Cocktail sort with shifting bounds \| Comb sort \| Cycle sort \| Gnome sort \| Insertion sort \| Selection sort \| Strand sort other sorts Bead sort \| Bogo sort \| Common sorted list \| Composite structures sort \| Custom comparator sort \| Counting sort \| Disjoint sublist sort \| External sort \| Jort sort \| Lexicographical sort \| Natural sorting \| Order by pair comparisons \| Order disjoint list items \| Order two numerical lists \| Object identifier (OID) sort \| Pancake sort \| Quickselect \| Permutation sort \| Radix sort \| Ranking methods \| Remove duplicate elements \| Sleep sort \| Stooge sort \| [Sort letters of a string] \| Three variable sort \| Topological sort \| Tree sort Given an Array, derive a sequence of elements in which all duplicates are removed. There are basically three approaches seen here: Put the elements into a hash table which does not allow duplicates. The complexity is O(n) on average, and O(n2) worst case. This approach requires a hash function for your type (which is compatible with equality), either built-in to your language, or provided by the user. Sort the elements and remove consecutive duplicate elements. The complexity of the best sorting algorithms is O(n log n). This approach requires that your type be "comparable", i.e., have an ordering. Putting the elements into a self-balancing binary search tree is a special case of sorting. Go through the list, and for each element, check the rest of the list to see if it appears again, and discard it if it does. The complexity is O(n2). The up-shot is that this always works on any type (provided that you can test for equality).	#F.23	F#	set [\|1;2;3;2;3;4\|]
http://rosettacode.org/wiki/Recaman%27s_sequence	Recaman's sequence	The Recamán's sequence generates Natural numbers. Starting from a(0)=0, the n'th term a(n), where n>0, is the previous term minus n i.e a(n) = a(n-1) - n but only if this is both positive and has not been previousely generated. If the conditions don't hold then a(n) = a(n-1) + n. Task Generate and show here the first 15 members of the sequence. Find and show here, the first duplicated number in the sequence. Optionally: Find and show here, how many terms of the sequence are needed until all the integers 0..1000, inclusive, are generated. References A005132, The On-Line Encyclopedia of Integer Sequences. The Slightly Spooky Recamán Sequence, Numberphile video. Recamán's sequence, on Wikipedia.	#PL.2FM	PL/M	100H: BDOS: PROCEDURE(F,A); DECLARE F BYTE, A ADDRESS; GO TO 5; END BDOS; EXIT: PROCEDURE; CALL BDOS(0,0); END EXIT; PRINT$CH: PROCEDURE(C); DECLARE C BYTE; CALL BDOS(2,C); END PRINT$CH; PRINT$STR: PROCEDURE(S); DECLARE S ADDRESS; CALL BDOS(9,S); END PRINT$STR; /* PRINT NUMBER / PRINT$NUM: PROCEDURE(N); DECLARE (N, P) ADDRESS, C BASED P BYTE; DECLARE S(6) BYTE INITIAL('.....$'); P = .S(5); DIGIT: P = P-1; C = '0' + N MOD 10; N = N/10; IF N>0 THEN GO TO DIGIT; CALL PRINT$STR(P); END PRINT$NUM; / IS X IN THE FIRST N TERMS OF THE SEQUENCE / FIND: PROCEDURE(SEQ,X,N) BYTE; DECLARE SEQ ADDRESS, (I, X, N, A BASED SEQ) BYTE; DO I=0 TO N-1; IF A(I)=X THEN RETURN 0FFH; END; RETURN 0; END FIND; / GENERATE THE N'TH TERM OF THE SEQUENCE / GENERATE: PROCEDURE(SEQ,N) BYTE; DECLARE SEQ ADDRESS, (N, A BASED SEQ) BYTE; IF N=0 THEN A(N)=0; ELSE DO; DECLARE (SUB, ADD) BYTE; SUB = A(N-1) - N; ADD = A(N-1) + N; / A(N-1) - N NEGATIVE? / IF A(N-1) <= N THEN A(N) = ADD; / A(N-1) - N ALREADY GENERATED? */ ELSE IF FIND(SEQ,SUB,N) THEN A(N) = ADD; ELSE A(N) = SUB; END; RETURN A(N); END GENERATE; DECLARE I BYTE, A(30) BYTE; CALL PRINT$STR(.'FIRST 15 MEMBERS: $'); DO I=0 TO 14; CALL PRINT$NUM(GENERATE(.A, I)); CALL PRINT$CH(' '); END; CALL PRINT$STR(.(13,10,'FIRST REPEATED TERM: A($')); I=15; DO WHILE NOT FIND(.A, GENERATE(.A, I), I); I = I+1; END; CALL PRINT$NUM(I); CALL PRINT$STR(.') = $'); CALL PRINT$NUM(A(I)); CALL PRINT$STR(.(13,10,'$')); CALL EXIT; EOF
http://rosettacode.org/wiki/Reduced_row_echelon_form	Reduced row echelon form	Reduced row echelon form You are encouraged to solve this task according to the task description, using any language you may know. Task Show how to compute the reduced row echelon form (a.k.a. row canonical form) of a matrix. The matrix can be stored in any datatype that is convenient (for most languages, this will probably be a two-dimensional array). Built-in functions or this pseudocode (from Wikipedia) may be used: function ToReducedRowEchelonForm(Matrix M) is lead := 0 rowCount := the number of rows in M columnCount := the number of columns in M for 0 ≤ r < rowCount do if columnCount ≤ lead then stop end if i = r while M[i, lead] = 0 do i = i + 1 if rowCount = i then i = r lead = lead + 1 if columnCount = lead then stop end if end if end while Swap rows i and r If M[r, lead] is not 0 divide row r by M[r, lead] for 0 ≤ i < rowCount do if i ≠ r do Subtract M[i, lead] multiplied by row r from row i end if end for lead = lead + 1 end for end function For testing purposes, the RREF of this matrix: 1 2 -1 -4 2 3 -1 -11 -2 0 -3 22 is: 1 0 0 -8 0 1 0 1 0 0 1 -2	#Java	Java	import java.util.; import java.lang.Math; import org.apache.commons.math.fraction.Fraction; import org.apache.commons.math.fraction.FractionConversionException; / Matrix class * Handles elementary Matrix operations: * Interchange * Multiply and Add * Scale * Reduced Row Echelon Form / class Matrix { LinkedList<LinkedList<Fraction>> matrix; int numRows; int numCols; static class Coordinate { int row; int col; Coordinate(int r, int c) { row = r; col = c; } public String toString() { return "(" + row + ", " + col + ")"; } } Matrix(double [][] m) { numRows = m.length; numCols = m[0].length; matrix = new LinkedList<LinkedList<Fraction>>(); for (int i = 0; i < numRows; i++) { matrix.add(new LinkedList<Fraction>()); for (int j = 0; j < numCols; j++) { try { matrix.get(i).add(new Fraction(m[i][j])); } catch (FractionConversionException e) { System.err.println("Fraction could not be converted from double by apache commons . . ."); } } } } public void Interchange(Coordinate a, Coordinate b) { LinkedList<Fraction> temp = matrix.get(a.row); matrix.set(a.row, matrix.get(b.row)); matrix.set(b.row, temp); int t = a.row; a.row = b.row; b.row = t; } public void Scale(Coordinate x, Fraction d) { LinkedList<Fraction> row = matrix.get(x.row); for (int i = 0; i < numCols; i++) { row.set(i, row.get(i).multiply(d)); } } public void MultiplyAndAdd(Coordinate to, Coordinate from, Fraction scalar) { LinkedList<Fraction> row = matrix.get(to.row); LinkedList<Fraction> rowMultiplied = matrix.get(from.row); for (int i = 0; i < numCols; i++) { row.set(i, row.get(i).add((rowMultiplied.get(i).multiply(scalar)))); } } public void RREF() { Coordinate pivot = new Coordinate(0,0); int submatrix = 0; for (int x = 0; x < numCols; x++) { pivot = new Coordinate(pivot.row, x); //Step 1 //Begin with the leftmost nonzero column. This is a pivot column. The pivot position is at the top. for (int i = x; i < numCols; i++) { if (isColumnZeroes(pivot) == false) { break; } else { pivot.col = i; } } //Step 2 //Select a nonzero entry in the pivot column with the highest absolute value as a pivot. pivot = findPivot(pivot); if (getCoordinate(pivot).doubleValue() == 0.0) { pivot.row++; continue; } //If necessary, interchange rows to move this entry into the pivot position. //move this row to the top of the submatrix if (pivot.row != submatrix) { Interchange(new Coordinate(submatrix, pivot.col), pivot); } //Force pivot to be 1 if (getCoordinate(pivot).doubleValue() != 1) { / System.out.println(getCoordinate(pivot)); System.out.println(pivot); System.out.println(matrix); / Fraction scalar = getCoordinate(pivot).reciprocal(); Scale(pivot, scalar); } //Step 3 //Use row replacement operations to create zeroes in all positions below the pivot. //belowPivot = belowPivot + (Pivot -belowPivot) for (int i = pivot.row; i < numRows; i++) { if (i == pivot.row) { continue; } Coordinate belowPivot = new Coordinate(i, pivot.col); Fraction complement = (getCoordinate(belowPivot).negate().divide(getCoordinate(pivot))); MultiplyAndAdd(belowPivot, pivot, complement); } //Step 5 //Beginning with the rightmost pivot and working upward and to the left, create zeroes above each pivot. //If a pivot is not 1, make it 1 by a scaling operation. //Use row replacement operations to create zeroes in all positions above the pivot for (int i = pivot.row; i >= 0; i--) { if (i == pivot.row) { if (getCoordinate(pivot).doubleValue() != 1.0) { Scale(pivot, getCoordinate(pivot).reciprocal()); } continue; } if (i == pivot.row) { continue; } Coordinate abovePivot = new Coordinate(i, pivot.col); Fraction complement = (getCoordinate(abovePivot).negate().divide(getCoordinate(pivot))); MultiplyAndAdd(abovePivot, pivot, complement); } //Step 4 //Ignore the row containing the pivot position and cover all rows, if any, above it. //Apply steps 1-3 to the remaining submatrix. Repeat until there are no more nonzero entries. if ((pivot.row + 1) >= numRows \|\| isRowZeroes(new Coordinate(pivot.row+1, pivot.col))) { break; } submatrix++; pivot.row++; } } public boolean isColumnZeroes(Coordinate a) { for (int i = 0; i < numRows; i++) { if (matrix.get(i).get(a.col).doubleValue() != 0.0) { return false; } } return true; } public boolean isRowZeroes(Coordinate a) { for (int i = 0; i < numCols; i++) { if (matrix.get(a.row).get(i).doubleValue() != 0.0) { return false; } } return true; } public Coordinate findPivot(Coordinate a) { int first_row = a.row; Coordinate pivot = new Coordinate(a.row, a.col); Coordinate current = new Coordinate(a.row, a.col); for (int i = a.row; i < (numRows - first_row); i++) { current.row = i; if (getCoordinate(current).doubleValue() == 1.0) { Interchange(current, a); } } current.row = a.row; for (int i = current.row; i < (numRows - first_row); i++) { current.row = i; if (getCoordinate(current).doubleValue() != 0) { pivot.row = i; break; } } return pivot; } public Fraction getCoordinate(Coordinate a) { return matrix.get(a.row).get(a.col); } public String toString() { return matrix.toString().replace("], ", "]\n"); } public static void main (String[] args) { double[][] matrix_1 = { {1, 2, -1, -4}, {2, 3, -1, -11}, {-2, 0, -3, 22} }; Matrix x = new Matrix(matrix_1); System.out.println("before\n" + x.toString() + "\n"); x.RREF(); System.out.println("after\n" + x.toString() + "\n"); double matrix_2 [][] = { {2, 0, -1, 0, 0}, {1, 0, 0, -1, 0}, {3, 0, 0, -2, -1}, {0, 1, 0, 0, -2}, {0, 1, -1, 0, 0} }; Matrix y = new Matrix(matrix_2); System.out.println("before\n" + y.toString() + "\n"); y.RREF(); System.out.println("after\n" + y.toString() + "\n"); double matrix_3 [][] = { {1, 2, 3, 4, 3, 1}, {2, 4, 6, 2, 6, 2}, {3, 6, 18, 9, 9, -6}, {4, 8, 12, 10, 12, 4}, {5, 10, 24, 11, 15, -4} }; Matrix z = new Matrix(matrix_3); System.out.println("before\n" + z.toString() + "\n"); z.RREF(); System.out.println("after\n" + z.toString() + "\n"); double matrix_4 [][] = { {0, 1}, {1, 2}, {0,5} }; Matrix a = new Matrix(matrix_4); System.out.println("before\n" + a.toString() + "\n"); a.RREF(); System.out.println("after\n" + a.toString() + "\n"); } }
http://rosettacode.org/wiki/Real_constants_and_functions	Real constants and functions	Task Show how to use the following math constants and functions in your language (if not available, note it): e (base of the natural logarithm) π {\displaystyle \pi } square root logarithm (any base allowed) exponential (ex ) absolute value (a.k.a. "magnitude") floor (largest integer less than or equal to this number--not the same as truncate or int) ceiling (smallest integer not less than this number--not the same as round up) power (xy ) Related task Trigonometric Functions	#Forth	Forth	1e fexp fconstant e 0e facos 2e f* fconstant pi \ predefined in gforth fsqrt ( f -- f ) fln ( f -- f ) \ flog for base 10 fexp ( f -- f ) fabs ( f -- f ) floor ( f -- f ) \ round towards -inf : ceil ( f -- f ) fnegate floor fnegate ; \ not standard, though fround is available f** ( f e -- f^e )
http://rosettacode.org/wiki/Real_constants_and_functions	Real constants and functions	Task Show how to use the following math constants and functions in your language (if not available, note it): e (base of the natural logarithm) π {\displaystyle \pi } square root logarithm (any base allowed) exponential (ex ) absolute value (a.k.a. "magnitude") floor (largest integer less than or equal to this number--not the same as truncate or int) ceiling (smallest integer not less than this number--not the same as round up) power (xy ) Related task Trigonometric Functions	#Fortran	Fortran	e ! Not available. Can be calculated EXP(1.0) pi ! Not available. Can be calculated 4.0ATAN(1.0) SQRT(x) ! square root LOG(x) ! natural logarithm LOG10(x) ! logarithm to base 10 EXP(x) ! exponential ABS(x) ! absolute value FLOOR(x) ! floor - Fortran 90 or later only CEILING(x) ! ceiling - Fortran 90 or later only x*y ! x raised to the y power
http://rosettacode.org/wiki/Remove_lines_from_a_file	Remove lines from a file	Task Remove a specific line or a number of lines from a file. This should be implemented as a routine that takes three parameters (filename, starting line, and the number of lines to be removed). For the purpose of this task, line numbers and the number of lines start at one, so to remove the first two lines from the file foobar.txt, the parameters should be: foobar.txt, 1, 2 Empty lines are considered and should still be counted, and if the specified line is empty, it should still be removed. An appropriate message should appear if an attempt is made to remove lines beyond the end of the file.	#Oforth	Oforth	: removeLines(filename, startLine, numLines) \| line b endLine \| ListBuffer new ->b startLine numLines + 1 - ->endLine 0 File new(filename) forEach: line [ 1+ dup between(startLine, endLine) ifFalse: [ b add(line) continue ] numLines 1- ->numLines ] drop numLines 0 == ifFalse: [ "Error : Removing lines beyond end of file" println return ] File new(filename) dup open(File.WRITE) b apply(#[ << dup cr ]) close ;
http://rosettacode.org/wiki/Remove_lines_from_a_file	Remove lines from a file	Task Remove a specific line or a number of lines from a file. This should be implemented as a routine that takes three parameters (filename, starting line, and the number of lines to be removed). For the purpose of this task, line numbers and the number of lines start at one, so to remove the first two lines from the file foobar.txt, the parameters should be: foobar.txt, 1, 2 Empty lines are considered and should still be counted, and if the specified line is empty, it should still be removed. An appropriate message should appear if an attempt is made to remove lines beyond the end of the file.	#Pascal	Pascal	program RemLines; {$mode objfpc}{$H+} uses {$IFDEF UNIX}{$IFDEF UseCThreads} cthreads, {$ENDIF}{$ENDIF} Classes, SysUtils; type TRLResponse=(rlrOk, rlrEmptyFile, rlrNotEnoughLines); function RemoveLines(const FileName: String; const From, Count: Integer): TRLResponse; const LineOffs = Length(LineEnding); var TIn, TOut: TFileStream; tmpFn, MemBuff, FileBuff: String; EndingPos, CharRead, LineNumber: Integer; procedure WriteLine(Line: String); begin if ((From > 1) and (LineNumber = 1)) or ((From = 1) and (LineNumber = (From+Count))) then // First line to write, without LineEnding => Line unchanged else if ((From = 1) or (From <= LineNumber)) and (LineNumber < (From+Count)) then // No line to write Line := '' else // all other cases, write Line preceded (!) by LineEnding Line := LineEnding + Line; // Write if Line <> '' then TOut.Write(Line[1], Length(Line)); End; begin if not FileExists(FileName) then raise Exception.CreateFmt('No such file %s', [FileName]); if From < 1 then raise Exception.Create('First line must be >= 1'); tmpFn := GetTempFileName(ExtractFilePath(FileName), ''); TIn := TFileStream.Create(FileName, fmOpenRead); try TOut := TFileStream.Create(tmpFn, fmCreate); try FileBuff := StringOfChar(' ', 1024); // Reserve memory in a string LineNumber := 0; MemBuff := ''; while True do begin CharRead := TIn.Read(FileBuff[1], 1024); if (CharRead = 0) then break; // no more char to process MemBuff += Copy(FileBuff, 1, CharRead); // op += is FPC specific while True do begin // LineEnding can contain 1 or 2 chars, depending on the OS EndingPos := Pos(LineEnding, MemBuff); if EndingPos = 0 then break; // EndingLine in the next reading, maybe Inc(LineNumber); WriteLine(Copy(MemBuff, 1, EndingPos - 1)); MemBuff := Copy(MemBuff, EndingPos + LineOffs, MaxInt); // Loop for another line in MemBuff end; end; Inc(LineNumber); WriteLine(MemBuff); // Writes what remains finally TOut.Free; end; finally TIn.Free; end; // Temp File replaces the original file. if DeleteFile(FileName) then RenameFile(tmpFn, FileName) else raise Exception.Create('Unable to process the file'); // Response if (LineNumber = 0) then Result := rlrEmptyFile else if (LineNumber < (From+Count-1)) then Result := rlrNotEnoughLines else Result := rlrOk; End; var FileName: String; begin FileName := IncludeTrailingPathDelimiter(ExtractFilePath(ParamStr(0))) + 'test.txt'; try case RemoveLines(FileName, 4, 3) of rlrOk: WriteLn('Lines deleted'); rlrEmptyFile: WriteLn(Format('File "%s" is empty!', [FileName])); rlrNotEnoughLines: WriteLn('Can''t delete lines past the end of file'); end except on E: Exception do WriteLn('Error: ' + E.Message); end; ReadLn; End.
http://rosettacode.org/wiki/Read_entire_file	Read entire file	Task Load the entire contents of some text file as a single string variable. If applicable, discuss: encoding selection, the possibility of memory-mapping. Of course, in practice one should avoid reading an entire file at once if the file is large and the task can be accomplished incrementally instead (in which case check File IO); this is for those cases where having the entire file is actually what is wanted.	#GUISS	GUISS	Start,Programs,Accessories,Notepad,Menu:File,Open,Doubleclick:Icon:Notes.TXT,Button:OK
http://rosettacode.org/wiki/Read_entire_file	Read entire file	Task Load the entire contents of some text file as a single string variable. If applicable, discuss: encoding selection, the possibility of memory-mapping. Of course, in practice one should avoid reading an entire file at once if the file is large and the task can be accomplished incrementally instead (in which case check File IO); this is for those cases where having the entire file is actually what is wanted.	#Haskell	Haskell	do text <- readFile filepath -- do stuff with text
http://rosettacode.org/wiki/Rep-string	Rep-string	Given a series of ones and zeroes in a string, define a repeated string or rep-string as a string which is created by repeating a substring of the first N characters of the string truncated on the right to the length of the input string, and in which the substring appears repeated at least twice in the original. For example, the string 10011001100 is a rep-string as the leftmost four characters of 1001 are repeated three times and truncated on the right to give the original string. Note that the requirement for having the repeat occur two or more times means that the repeating unit is never longer than half the length of the input string. Task Write a function/subroutine/method/... that takes a string and returns an indication of if it is a rep-string and the repeated string. (Either the string that is repeated, or the number of repeated characters would suffice). There may be multiple sub-strings that make a string a rep-string - in that case an indication of all, or the longest, or the shortest would suffice. Use the function to indicate the repeating substring if any, in the following: 1001110011 1110111011 0010010010 1010101010 1111111111 0100101101 0100100 101 11 00 1 Show your output on this page. Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet	#PL.2FM	PL/M	100H: DECLARE MAX$REP LITERALLY '32'; DECLARE FALSE LITERALLY '0'; DECLARE TRUE LITERALLY '1'; DECLARE CR LITERALLY '0DH'; DECLARE LF LITERALLY '0AH'; /* CP/M BDOS SYSTEM CALL / BDOS: PROCEDURE( FN, ARG ); DECLARE FN BYTE, ARG ADDRESS; GOTO 5; END; / PRINTS A BYTE AS A CHARACTER / PRINT$CHAR: PROCEDURE( CH ); DECLARE CH BYTE; CALL BDOS( 2, CH ); END; / PRINTS A $ TERMINATED STRING / PRINT$STRING: PROCEDURE( S ); DECLARE S ADDRESS; CALL BDOS( 9, S ); END; / PRINTS A BYTE AS A NUMBER / PRINT$BYTE: PROCEDURE( N ); DECLARE N BYTE; DECLARE ( V, D2, D3 ) BYTE; V = N; D3 = V MOD 10; IF ( V := V / 10 ) <> 0 THEN DO; D2 = V MOD 10; IF ( V := V / 10 ) <> 0 THEN CALL PRINT$CHAR( '0' + V ); CALL PRINT$CHAR( '0' + D2 ); END; CALL PRINT$CHAR( '0' + D3 ); END PRINT$BYTE; / PRINTS A FIXED LENGTH STRING / PRINT$SUBSTRING: PROCEDURE( S$PTR, LEN ); DECLARE S$PTR ADDRESS, LEN BYTE, S BASED S$PTR ( MAX$REP )BYTE; DECLARE S$POS BYTE; DO S$POS = 0 TO LEN - 1; CALL PRINT$CHAR( S( S$POS ) ); END; END PRINT$SUBSTRING; / RETURNS THE LENGTH OF A $ TERMINATED STRING / STR$LENGTH: PROCEDURE( S$PTR )BYTE; DECLARE S$PTR ADDRESS, S BASED S$PTR ( MAX$REP )BYTE; DECLARE RESULT BYTE; RESULT = 0; DO WHILE( S( RESULT ) <> '$' ); RESULT = RESULT + 1; END; RETURN RESULT; END STR$LENGTH; / RETURNS THE LENGTH OF THE LONGEST REP-STRING IN S$PTR, / LONGEST$REP$STRING: PROCEDURE( S$PTR )BYTE; DECLARE S$PTR ADDRESS, S BASED S$PTR ( MAX$REP )BYTE; DECLARE ( S$LEN, RESULT, S$POS, R$POS, I, FOUND ) BYTE; RESULT = 0; FOUND = FALSE; S$LEN = STR$LENGTH( S$PTR ); S$POS = ( S$LEN / 2 ) - 1; / IF ( S$LEN / 2 ) = 0, S$POS WILL BE 255 / DO WHILE( NOT FOUND AND S$POS < 255 ); / AS BYTE/ADDRESS ARE UNSIGNED / / CHECK THE POTENTIAL REP-STRING REPEATED A SUFFICIENT NUMBER / / OF TIMES (TRUNCATED IF NECESSARY) EQUALS THE ORIGINAL STRING / FOUND = TRUE; R$POS = S$POS + 1; DO WHILE( FOUND AND R$POS < S$LEN AND FOUND ); I = 0; DO WHILE( I <= S$POS AND R$POS < S$LEN AND FOUND ); FOUND = S( R$POS ) = S( I ); R$POS = R$POS + 1; I = I + 1; END; END; IF NOT FOUND THEN DO; / HAVEN'T FOUND A REP-STRING, TRY A SHORTER ONE / S$POS = S$POS - 1; / S$POS WILL BECOME 255 IF S$POS = 0 */ END; END; IF FOUND THEN DO; RESULT = S$POS + 1; END; RETURN RESULT; END LONGEST$REP$STRING; DECLARE ( TEST$NUMBER, REP$STRING$LEN ) BYTE; DECLARE TESTS ( 11 )ADDRESS; TESTS( 0 ) = .'1001110011$'; TESTS( 1 ) = .'1110111011$'; TESTS( 2 ) = .'0010010010$'; TESTS( 3 ) = .'1010101010$'; TESTS( 4 ) = .'1111111111$'; TESTS( 5 ) = .'0100101101$'; TESTS( 6 ) = .'0100100$'; TESTS( 7 ) = .'101$'; TESTS( 8 ) = .'11$'; TESTS( 9 ) = .'00$'; TESTS( 10 ) = .'1$'; DO TEST$NUMBER = 0 TO LAST( TESTS ); REP$STRING$LEN = LONGEST$REP$STRING( TESTS( TEST$NUMBER ) ); CALL PRINT$STRING( TESTS( TEST$NUMBER ) ); IF REP$STRING$LEN = 0 THEN DO; CALL PRINT$STRING( .': NO REP STRING$' ); END; ELSE DO; CALL PRINT$STRING( .': LONGEST REP STRING: $' ); CALL PRINT$SUBSTRING( TESTS( TEST$NUMBER ), REP$STRING$LEN ); END; CALL PRINT$STRING( .( CR, LF, '$' ) ); END; EOF
http://rosettacode.org/wiki/Rep-string	Rep-string	Given a series of ones and zeroes in a string, define a repeated string or rep-string as a string which is created by repeating a substring of the first N characters of the string truncated on the right to the length of the input string, and in which the substring appears repeated at least twice in the original. For example, the string 10011001100 is a rep-string as the leftmost four characters of 1001 are repeated three times and truncated on the right to give the original string. Note that the requirement for having the repeat occur two or more times means that the repeating unit is never longer than half the length of the input string. Task Write a function/subroutine/method/... that takes a string and returns an indication of if it is a rep-string and the repeated string. (Either the string that is repeated, or the number of repeated characters would suffice). There may be multiple sub-strings that make a string a rep-string - in that case an indication of all, or the longest, or the shortest would suffice. Use the function to indicate the repeating substring if any, in the following: 1001110011 1110111011 0010010010 1010101010 1111111111 0100101101 0100100 101 11 00 1 Show your output on this page. Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet	#Prolog	Prolog	:- use_module(library(func)). %% Implementation logic: test_for_repstring(String, (String, Result, Reps)) :- ( setof(Rep, repstring(String, Rep), Reps) -> Result = 'no repstring' ; Result = 'repstrings', Reps = [] ). repstring(Codes, R) :- RepLength = between(1) of (_//2) of length $ Codes, length(R, RepLength), phrase( (rep(R), prefix(~,R)), Codes). rep(X) --> X, X. rep(X) --> X, rep(X). %% Demonstration output: test_strings([`1001110011`, `1110111011`, `0010010010`, `1010101010`, `1111111111`, `0100101101`, `0100100`, `101`, `11`, `00`, `1`]). report_repstring((S,Result,Reps)):- format('~s -- ~w: ', [S, Result]), foreach(member(R, Reps), format('~s, ', [R])), nl. report_repstrings :- Results = maplist(test_for_repstring) $ test_strings(~), maplist(report_repstring, Results).
http://rosettacode.org/wiki/Regular_expressions	Regular expressions	Task match a string against a regular expression substitute part of a string using a regular expression	#Oz	Oz	declare [Regex] = {Module.link ['x-oz://contrib/regex']} String = "This is a string" in if {Regex.search "string$" String} \= false then {System.showInfo "Ends with string."} end {System.showInfo {Regex.replace String " a " fun {$ _ _} " another " end}}
http://rosettacode.org/wiki/Regular_expressions	Regular expressions	Task match a string against a regular expression substitute part of a string using a regular expression	#Pascal	Pascal	// Match and Replace part of a string using a Regular Expression // // Nigel Galloway - April 11th., 2012 // program RegularExpr; uses RegExpr; const myString = 'I think that I am Nigel'; myMatch = '(I am)\|(you are)'; var r : TRegExpr; myResult : String; begin r := TRegExpr.Create; r.Expression := myMatch; write(myString); if r.Exec(myString) then writeln(' contains ' + r.Match[0]); myResult := r.Replace(myString, 'you are', False); write(myResult); if r.Exec(myResult) then writeln(' contains ' + r.Match[0]); end.
http://rosettacode.org/wiki/Reverse_a_string	Reverse a string	Task Take a string and reverse it. For example, "asdf" becomes "fdsa". Extra credit Preserve Unicode combining characters. For example, "as⃝df̅" becomes "f̅ds⃝a", not "̅fd⃝sa". Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet	#ColdFusion	ColdFusion	<cfset myString = "asdf" /> <cfset myString = reverse( myString ) />
http://rosettacode.org/wiki/Repeat	Repeat	Task Write a procedure which accepts as arguments another procedure and a positive integer. The latter procedure is executed a number of times equal to the accepted integer.	#Verilog	Verilog	module main; initial begin repeat(5) begin $display("Inside loop"); end $display("Loop Ended"); end endmodule
http://rosettacode.org/wiki/Repeat	Repeat	Task Write a procedure which accepts as arguments another procedure and a positive integer. The latter procedure is executed a number of times equal to the accepted integer.	#Visual_Basic_.NET	Visual Basic .NET	Module Module1 Sub Repeat(count As Integer, fn As Action(Of Integer)) If IsNothing(fn) Then Throw New ArgumentNullException("fn") End If For i = 1 To count fn.Invoke(i) Next End Sub Sub Main() Repeat(3, Sub(x) Console.WriteLine("Example {0}", x)) End Sub End Module
http://rosettacode.org/wiki/Rename_a_file	Rename a file	Task Rename: a file called input.txt into output.txt and a directory called docs into mydocs. This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root. It can be assumed that the user has the rights to do so. (In unix-type systems, only the user root would have sufficient permissions in the filesystem root.)	#PureBasic	PureBasic	RenameFile("input.txt", "output.txt") RenameFile("docs\", "mydocs\") RenameFile("/input.txt","/output.txt") RenameFile("/docs\","/mydocs\")

http://rosettacode.org/wiki/Rot-13

Rot-13

Task Implement a rot-13 function (or procedure, class, subroutine, or other "callable" object as appropriate to your programming environment). Optionally wrap this function in a utility program (like tr, which acts like a common UNIX utility, performing a line-by-line rot-13 encoding of every line of input contained in each file listed on its command line, or (if no filenames are passed thereon) acting as a filter on its "standard input." (A number of UNIX scripting languages and utilities, such as awk and sed either default to processing files in this way or have command line switches or modules to easily implement these wrapper semantics, e.g., Perl and Python). The rot-13 encoding is commonly known from the early days of Usenet "Netnews" as a way of obfuscating text to prevent casual reading of spoiler or potentially offensive material. Many news reader and mail user agent programs have built-in rot-13 encoder/decoders or have the ability to feed a message through any external utility script for performing this (or other) actions. The definition of the rot-13 function is to simply replace every letter of the ASCII alphabet with the letter which is "rotated" 13 characters "around" the 26 letter alphabet from its normal cardinal position (wrapping around from z to a as necessary). Thus the letters abc become nop and so on. Technically rot-13 is a "mono-alphabetic substitution cipher" with a trivial "key". A proper implementation should work on upper and lower case letters, preserve case, and pass all non-alphabetic characters in the input stream through without alteration. Related tasks Caesar cipher Substitution Cipher Vigenère Cipher/Cryptanalysis Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet

#Simula

Simula

TEXT PROCEDURE ROT13(INP); TEXT INP; BEGIN CHARACTER PROCEDURE ROT13CHAR(C); CHARACTER C; ROT13CHAR := CHAR( RANK(C) + (IF C >= 'A' AND C <= 'M' THEN 13 ELSE IF C >= 'a' AND C <= 'm' THEN 13 ELSE IF C >= 'N' AND C <= 'Z' THEN -13 ELSE IF C >= 'n' AND C <= 'z' THEN -13 ELSE 0)); TEXT OUTP; OUTP :- BLANKS(INP.LENGTH); INP.SETPOS(1); WHILE INP.MORE DO OUTP.PUTCHAR(ROT13CHAR(INP.GETCHAR)); ROT13 :- OUTP; END ROT13;

http://rosettacode.org/wiki/Roman_numerals/Encode

Roman numerals/Encode

Task Create a function taking a positive integer as its parameter and returning a string containing the Roman numeral representation of that integer. Modern Roman numerals are written by expressing each digit separately, starting with the left most digit and skipping any digit with a value of zero. In Roman numerals: 1990 is rendered: 1000=M, 900=CM, 90=XC; resulting in MCMXC 2008 is written as 2000=MM, 8=VIII; or MMVIII 1666 uses each Roman symbol in descending order: MDCLXVI

#SenseTalk

SenseTalk

function RomanNumeralsEncode number put [ (1, "I"), (4, "IV"), (5, "V"), (9, "IX"), (10, "X"), (40, "XL"), (50, "L"), (90, "XC"), (100, "C"), (400, "CD"), (500, "D"), (900, "CM"), (1000, "M") ] into values repeat for index = each item of (the number of items in values)..1 put item index of values into pair repeat while number is greater than or equal to the first item of pair put the second item of pair after numerals subtract the first item of pair from number end repeat end repeat return numerals end RomanNumeralsEncode

http://rosettacode.org/wiki/Roman_numerals/Decode

Roman numerals/Decode

Task Create a function that takes a Roman numeral as its argument and returns its value as a numeric decimal integer. You don't need to validate the form of the Roman numeral. Modern Roman numerals are written by expressing each decimal digit of the number to be encoded separately, starting with the leftmost decimal digit and skipping any 0s (zeroes). 1990 is rendered as MCMXC (1000 = M, 900 = CM, 90 = XC) and 2008 is rendered as MMVIII (2000 = MM, 8 = VIII). The Roman numeral for 1666, MDCLXVI, uses each letter in descending order.

#XPL0

XPL0

string 0; \use zero-terminated strings code CrLf=9, IntOut=11; func Roman(Str); \Convert Roman numeral string to decimal value char Str; int I, Val, Val0, Sum; [I:= 0; Sum:= 0; Val0:= 5000; loop [case Str(I) of ^M: Val:= 1000; ^D: Val:= 500; ^C: Val:= 100; ^L: Val:= 50; ^X: Val:= 10; ^V: Val:= 5; ^I: Val:= 1 other return Sum; \zero string terminator I:= I+1; Sum:= Sum + Val; if Val > Val0 then Sum:= Sum - 2*Val0; Val0:= Val; ]; ]; [IntOut(0, Roman("MCMXC")); CrLf(0); IntOut(0, Roman("MMVIII")); CrLf(0); IntOut(0, Roman("MDCLXVI")); CrLf(0); ]

http://rosettacode.org/wiki/Repeat_a_string

Repeat a string

Take a string and repeat it some number of times. Example: repeat("ha", 5) => "hahahahaha" If there is a simpler/more efficient way to repeat a single “character” (i.e. creating a string filled with a certain character), you might want to show that as well (i.e. repeat-char("*", 5) => "*****"). Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet

#Free_Pascal

Free Pascal

strUtils.dupeString('ha', 5)

http://rosettacode.org/wiki/Repeat_a_string

Repeat a string

Take a string and repeat it some number of times. Example: repeat("ha", 5) => "hahahahaha" If there is a simpler/more efficient way to repeat a single “character” (i.e. creating a string filled with a certain character), you might want to show that as well (i.e. repeat-char("*", 5) => "*****"). Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet

#FreeBASIC

FreeBASIC

' FB 1.05.0 Win64 ' A character is essentially a string of length 1 in FB though there is a built-in function, String, ' which creates a string by repeating a character a given number of times. ' To avoid repeated concatenation (a slow operation) when the string to be repeated has a length ' greater than one, we instead create a buffer of the required size and then fill that. Function repeat(s As String, n As Integer) As String If n < 1 Then Return "" If n = 1 Then Return s Var size = Len(s) If size = 0 Then Return s ' empty string If size = 1 Then Return String(n, s[0]) ' repeated single character Var buffer = Space(size * n) 'create buffer for size > 1 For i As Integer = 0 To n - 1 For j As Integer = 0 To size - 1 buffer[i * size + j] = s[j] Next j Next i Return buffer End Function Print repeat("rosetta", 1) Print repeat("ha", 5) Print repeat("*", 5) Print Print "Press any key to quit program" Sleep

http://rosettacode.org/wiki/Return_multiple_values

Return multiple values

Task Show how to return more than one value from a function.

#PHP

PHP

function addsub($x, $y) { return array($x + $y, $x - $y); }

http://rosettacode.org/wiki/Return_multiple_values

Return multiple values

Task Show how to return more than one value from a function.

#Picat

Picat

main => [A,B,C] = fun(10), println([A,B,C]). fun(N) = [2*N-1,2*N,2*N+1].

http://rosettacode.org/wiki/Remove_duplicate_elements

Remove duplicate elements

Sorting Algorithm This is a sorting algorithm. It may be applied to a set of data in order to sort it. For comparing various sorts, see compare sorts. For other sorting algorithms, see sorting algorithms, or: O(n logn) sorts Heap sort | Merge sort | Patience sort | Quick sort O(n log2n) sorts Shell Sort O(n2) sorts Bubble sort | Cocktail sort | Cocktail sort with shifting bounds | Comb sort | Cycle sort | Gnome sort | Insertion sort | Selection sort | Strand sort other sorts Bead sort | Bogo sort | Common sorted list | Composite structures sort | Custom comparator sort | Counting sort | Disjoint sublist sort | External sort | Jort sort | Lexicographical sort | Natural sorting | Order by pair comparisons | Order disjoint list items | Order two numerical lists | Object identifier (OID) sort | Pancake sort | Quickselect | Permutation sort | Radix sort | Ranking methods | Remove duplicate elements | Sleep sort | Stooge sort | [Sort letters of a string] | Three variable sort | Topological sort | Tree sort Given an Array, derive a sequence of elements in which all duplicates are removed. There are basically three approaches seen here: Put the elements into a hash table which does not allow duplicates. The complexity is O(n) on average, and O(n2) worst case. This approach requires a hash function for your type (which is compatible with equality), either built-in to your language, or provided by the user. Sort the elements and remove consecutive duplicate elements. The complexity of the best sorting algorithms is O(n log n). This approach requires that your type be "comparable", i.e., have an ordering. Putting the elements into a self-balancing binary search tree is a special case of sorting. Go through the list, and for each element, check the rest of the list to see if it appears again, and discard it if it does. The complexity is O(n2). The up-shot is that this always works on any type (provided that you can test for equality).

#Elixir

Elixir

defmodule RC do # Set approach def uniq1(list), do: MapSet.new(list) |> MapSet.to_list # Sort approach def uniq2(list), do: Enum.sort(list) |> Enum.dedup # Go through the list approach def uniq3(list), do: uniq3(list, []) defp uniq3([], res), do: Enum.reverse(res) defp uniq3([h|t], res) do if h in res, do: uniq3(t, res), else: uniq3(t, [h | res]) end end num = 10000 max = div(num, 10) list = for _ <- 1..num, do: :rand.uniform(max) funs = [&Enum.uniq/1, &RC.uniq1/1, &RC.uniq2/1, &RC.uniq3/1] Enum.each(funs, fn fun -> result = fun.([1,1,2,1,'redundant',1.0,[1,2,3],[1,2,3],'redundant',1.0]) :timer.tc(fn -> Enum.each(1..100, fn _ -> fun.(list) end) end) |> fn{t,_} -> IO.puts "#{inspect fun}:\t#{t/1000000}\t#{inspect result}" end.() end)

http://rosettacode.org/wiki/Recaman%27s_sequence

Recaman's sequence

The Recamán's sequence generates Natural numbers. Starting from a(0)=0, the n'th term a(n), where n>0, is the previous term minus n i.e a(n) = a(n-1) - n but only if this is both positive and has not been previousely generated. If the conditions don't hold then a(n) = a(n-1) + n. Task Generate and show here the first 15 members of the sequence. Find and show here, the first duplicated number in the sequence. Optionally: Find and show here, how many terms of the sequence are needed until all the integers 0..1000, inclusive, are generated. References A005132, The On-Line Encyclopedia of Integer Sequences. The Slightly Spooky Recamán Sequence, Numberphile video. Recamán's sequence, on Wikipedia.

#Phix

Phix

with javascript_semantics bool found_duplicate = false sequence a = {0}, used = {} -- (grows to 1,942,300 entries) integer all_used = 0, n = 1, next, prev = 0 while n<=15 or not found_duplicate or all_used<1000 do next = prev - n if next<1 or (next<=length(used) and used[next]) then next = prev + n end if a &= next integer padlen = next-length(used) bool already_used = padlen<=0 and used[next] if not already_used then if padlen>0 then used &= repeat(false,padlen) end if used[next] = true while all_used<length(used) and used[all_used+1] do all_used += 1 end while end if if length(a)=15 then printf(1,"The first 15 terms of the Recaman sequence are: %v\n",{a}) end if if already_used and not found_duplicate then printf(1,"The first duplicated term is a[%d] = %d\n", {n, next}) found_duplicate = true; end if if all_used>=1000 then printf(1,"Terms up to a[%d] are needed to generate 0 to 1000\n", {n}); end if prev = next n += 1 end while

http://rosettacode.org/wiki/Reduced_row_echelon_form

Reduced row echelon form

Reduced row echelon form You are encouraged to solve this task according to the task description, using any language you may know. Task Show how to compute the reduced row echelon form (a.k.a. row canonical form) of a matrix. The matrix can be stored in any datatype that is convenient (for most languages, this will probably be a two-dimensional array). Built-in functions or this pseudocode (from Wikipedia) may be used: function ToReducedRowEchelonForm(Matrix M) is lead := 0 rowCount := the number of rows in M columnCount := the number of columns in M for 0 ≤ r < rowCount do if columnCount ≤ lead then stop end if i = r while M[i, lead] = 0 do i = i + 1 if rowCount = i then i = r lead = lead + 1 if columnCount = lead then stop end if end if end while Swap rows i and r If M[r, lead] is not 0 divide row r by M[r, lead] for 0 ≤ i < rowCount do if i ≠ r do Subtract M[i, lead] multiplied by row r from row i end if end for lead = lead + 1 end for end function For testing purposes, the RREF of this matrix: 1 2 -1 -4 2 3 -1 -11 -2 0 -3 22 is: 1 0 0 -8 0 1 0 1 0 0 1 -2

#Haskell

Haskell

import Data.List (find) rref :: Fractional a => [[a]] -> [[a]] rref m = f m 0 [0 .. rows - 1] where rows = length m cols = length $ head m f m _ [] = m f m lead (r : rs) | indices == Nothing = m | otherwise = f m' (lead' + 1) rs where indices = find p l p (col, row) = m !! row !! col /= 0 l = [(col, row) | col <- [lead .. cols - 1], row <- [r .. rows - 1]] Just (lead', i) = indices newRow = map (/ m !! i !! lead') $ m !! i m' = zipWith g [0..] $ replace r newRow $ replace i (m !! r) m g n row | n == r = row | otherwise = zipWith h newRow row where h = subtract . (* row !! lead') replace :: Int -> a -> [a] -> [a] {- Replaces the element at the given index. -} replace n e l = a ++ e : b where (a, _ : b) = splitAt n l

http://rosettacode.org/wiki/Real_constants_and_functions

Real constants and functions

Task Show how to use the following math constants and functions in your language (if not available, note it): e (base of the natural logarithm) π {\displaystyle \pi } square root logarithm (any base allowed) exponential (ex ) absolute value (a.k.a. "magnitude") floor (largest integer less than or equal to this number--not the same as truncate or int) ceiling (smallest integer not less than this number--not the same as round up) power (xy ) Related task Trigonometric Functions

#Elm

Elm

e -- e pi -- pi sqrt x -- square root logBase 3 9 -- logarithm (any base) e^x -- exponential abs x -- absolute value floor x -- floor ceiling x -- ceiling 2 ^ 3 -- power

http://rosettacode.org/wiki/Real_constants_and_functions

Real constants and functions

Task Show how to use the following math constants and functions in your language (if not available, note it): e (base of the natural logarithm) π {\displaystyle \pi } square root logarithm (any base allowed) exponential (ex ) absolute value (a.k.a. "magnitude") floor (largest integer less than or equal to this number--not the same as truncate or int) ceiling (smallest integer not less than this number--not the same as round up) power (xy ) Related task Trigonometric Functions

#Erlang

Erlang

% Implemented by Arjun Sunel -module(math_constants). -export([main/0]). main() -> io:format("~p~n", [math:exp(1)] ), % e io:format("~p~n", [math:pi()] ), % pi io:format("~p~n", [math:sqrt(16)] ), % square root io:format("~p~n", [math:log(10)] ), % natural logarithm io:format("~p~n", [math:log10(10)] ), % base 10 logarithm io:format("~p~n", [math:exp(2)] ), % e raised to the power of x io:format("~p~n", [abs(-2.24)] ), % absolute value io:format("~p~n", [floor(3.1423)] ), % floor io:format("~p~n", [ceil(20.125)] ), % ceiling io:format("~p~n", [math:pow(3,2)] ). % exponentiation floor(X) when X < 0 -> T = trunc(X), case X - T == 0 of true -> T; false -> T - 1 end; floor(X) -> trunc(X). ceil(X) when X < 0 -> trunc(X); ceil(X) -> T = trunc(X), case X - T == 0 of true -> T; false -> T + 1 end.

http://rosettacode.org/wiki/Remove_lines_from_a_file

Remove lines from a file

Task Remove a specific line or a number of lines from a file. This should be implemented as a routine that takes three parameters (filename, starting line, and the number of lines to be removed). For the purpose of this task, line numbers and the number of lines start at one, so to remove the first two lines from the file foobar.txt, the parameters should be: foobar.txt, 1, 2 Empty lines are considered and should still be counted, and if the specified line is empty, it should still be removed. An appropriate message should appear if an attempt is made to remove lines beyond the end of the file.

#Lua

Lua

function remove( filename, starting_line, num_lines ) local fp = io.open( filename, "r" ) if fp == nil then return nil end content = {} i = 1; for line in fp:lines() do if i < starting_line or i >= starting_line + num_lines then content[#content+1] = line end i = i + 1 end if i > starting_line and i < starting_line + num_lines then print( "Warning: Tried to remove lines after EOF." ) end fp:close() fp = io.open( filename, "w+" ) for i = 1, #content do fp:write( string.format( "%s\n", content[i] ) ) end fp:close() end

http://rosettacode.org/wiki/Read_entire_file

Read entire file

Task Load the entire contents of some text file as a single string variable. If applicable, discuss: encoding selection, the possibility of memory-mapping. Of course, in practice one should avoid reading an entire file at once if the file is large and the task can be accomplished incrementally instead (in which case check File IO); this is for those cases where having the entire file is actually what is wanted.

#FutureBasic

FutureBasic

_window = 1 begin enum 1 _scrollView _textView end enum void local fn BuildWindow CGRect r = {0,0,550,400} window _window, @"Read Entire File", r scrollview _scrollView, r ViewSetAutoresizingMask( _scrollView, NSViewWidthSizable + NSViewHeightSizable ) textview _textView,, _scrollView end fn local fn ReadTextFile CFStringRef string CFURLRef url = openpanel 1, @"Select text file..." if ( url ) string = fn StringWithContentsOfURL( url, NSUTF8StringEncoding, NULL ) TextSetString( _textView, string ) else // user cancelled end if end fn fn BuildWindow fn ReadTextFile HandleEvents

http://rosettacode.org/wiki/Read_entire_file

Read entire file

Task Load the entire contents of some text file as a single string variable. If applicable, discuss: encoding selection, the possibility of memory-mapping. Of course, in practice one should avoid reading an entire file at once if the file is large and the task can be accomplished incrementally instead (in which case check File IO); this is for those cases where having the entire file is actually what is wanted.

#Gambas

Gambas

Public Sub Form_Open() Dim sFile As String sFile = File.Load(User.home &/ "file.txt") End

http://rosettacode.org/wiki/Rep-string

Rep-string

Given a series of ones and zeroes in a string, define a repeated string or rep-string as a string which is created by repeating a substring of the first N characters of the string truncated on the right to the length of the input string, and in which the substring appears repeated at least twice in the original. For example, the string 10011001100 is a rep-string as the leftmost four characters of 1001 are repeated three times and truncated on the right to give the original string. Note that the requirement for having the repeat occur two or more times means that the repeating unit is never longer than half the length of the input string. Task Write a function/subroutine/method/... that takes a string and returns an indication of if it is a rep-string and the repeated string. (Either the string that is repeated, or the number of repeated characters would suffice). There may be multiple sub-strings that make a string a rep-string - in that case an indication of all, or the longest, or the shortest would suffice. Use the function to indicate the repeating substring if any, in the following: 1001110011 1110111011 0010010010 1010101010 1111111111 0100101101 0100100 101 11 00 1 Show your output on this page. Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet

#Perl

Perl

foreach (qw(1001110011 1110111011 0010010010 1010101010 1111111111 0100101101 0100100 101 11 00 1)) { print "$_\n"; if (/^(.+)\1+(.*$)(?(?{ substr($1, 0, length $2) eq $2 })|(?!))/) { print ' ' x length $1, "$1\n\n"; } else { print " (no repeat)\n\n"; } }

http://rosettacode.org/wiki/Rep-string

Rep-string

Given a series of ones and zeroes in a string, define a repeated string or rep-string as a string which is created by repeating a substring of the first N characters of the string truncated on the right to the length of the input string, and in which the substring appears repeated at least twice in the original. For example, the string 10011001100 is a rep-string as the leftmost four characters of 1001 are repeated three times and truncated on the right to give the original string. Note that the requirement for having the repeat occur two or more times means that the repeating unit is never longer than half the length of the input string. Task Write a function/subroutine/method/... that takes a string and returns an indication of if it is a rep-string and the repeated string. (Either the string that is repeated, or the number of repeated characters would suffice). There may be multiple sub-strings that make a string a rep-string - in that case an indication of all, or the longest, or the shortest would suffice. Use the function to indicate the repeating substring if any, in the following: 1001110011 1110111011 0010010010 1010101010 1111111111 0100101101 0100100 101 11 00 1 Show your output on this page. Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet

#Phix

Phix

function list_reps(string r) sequence replist = {} integer n = length(r) for m=1 to floor(n/2) do string s = r[1..m] if join(repeat(s,floor(n/m)+1),"")[1..n]=r then replist = append(replist,s) end if end for return replist end function constant tests = {"1001110011", "1110111011", "0010010010", "1010101010", "1111111111", "0100101101", "0100100", "101", "11", "00", "1"} for i=1 to length(tests) do printf(1,"%s\n",{tests[i]}) sequence replist = list_reps(tests[i]) if length(replist)=0 then printf(1,"not a rep-string.\n") else for j=1 to length(replist) do string rj = replist[j], pad = repeat(' ',length(rj)) printf(1,"%s%s\n",{pad,rj}) end for end if printf(1,"\n") end for

http://rosettacode.org/wiki/Regular_expressions

Regular expressions

Task match a string against a regular expression substitute part of a string using a regular expression

#OCaml

OCaml

#load "str.cma";; let str = "I am a string";; try ignore(Str.search_forward (Str.regexp ".*string$") str 0); print_endline "ends with 'string'" with Not_found -> () ;;

http://rosettacode.org/wiki/Regular_expressions

Regular expressions

Task match a string against a regular expression substitute part of a string using a regular expression

#Ol

Ol

; matching: (define regex (string->regex "m/aa(bb|cc)dd/")) (print (regex "aabbddx")) ; => true (print (regex "aaccddx")) ; => true (print (regex "aabcddx")) ; => false ; substitute part of a string: (define regex (string->regex "s/aa(bb|cc)dd/HAHAHA/")) (print (regex "aabbddx")) ; => HAHAHAx (print (regex "aaccddx")) ; => HAHAHAx (print (regex "aabcddx")) ; => false

http://rosettacode.org/wiki/Reverse_a_string

Reverse a string

Task Take a string and reverse it. For example, "asdf" becomes "fdsa". Extra credit Preserve Unicode combining characters. For example, "as⃝df̅" becomes "f̅ds⃝a", not "̅fd⃝sa". Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet

#CLU

CLU

reverse = proc (s: string) returns (string) rslt: array[char] := array[char]$predict(1,string$size(s)) for c: char in string$chars(s) do array[char]$addl(rslt,c) end return(string$ac2s(rslt)) end reverse start_up = proc () po: stream := stream$primary_output() stream$putl(po, reverse("!dlrow ,olleH")) end start_up

http://rosettacode.org/wiki/Repeat

Repeat

Task Write a procedure which accepts as arguments another procedure and a positive integer. The latter procedure is executed a number of times equal to the accepted integer.

#Stata

Stata

function repeat(f,n) { for (i=1; i<=n; i++) (*f)() } function hello() { printf("Hello\n") } repeat(&hello(),3)

http://rosettacode.org/wiki/Repeat

Repeat

Task Write a procedure which accepts as arguments another procedure and a positive integer. The latter procedure is executed a number of times equal to the accepted integer.

#Swift

Swift

func repeat(n: Int, f: () -> ()) { for _ in 0..<n { f() } } repeat(4) { println("Example") }

http://rosettacode.org/wiki/Rename_a_file

Rename a file

Task Rename: a file called input.txt into output.txt and a directory called docs into mydocs. This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root. It can be assumed that the user has the rights to do so. (In unix-type systems, only the user root would have sufficient permissions in the filesystem root.)

#PHP

PHP

<?php rename('input.txt', 'output.txt'); rename('docs', 'mydocs'); rename('/input.txt', '/output.txt'); rename('/docs', '/mydocs'); ?>

http://rosettacode.org/wiki/Rename_a_file

Rename a file

Task Rename: a file called input.txt into output.txt and a directory called docs into mydocs. This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root. It can be assumed that the user has the rights to do so. (In unix-type systems, only the user root would have sufficient permissions in the filesystem root.)

#PicoLisp

PicoLisp

(call 'mv "input.txt" "output.txt") (call 'mv "docs" "mydocs") (call 'mv "/input.txt" "/output.txt") (call 'mv "/docs" "/mydocs")

http://rosettacode.org/wiki/Rename_a_file

Rename a file

Task Rename: a file called input.txt into output.txt and a directory called docs into mydocs. This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root. It can be assumed that the user has the rights to do so. (In unix-type systems, only the user root would have sufficient permissions in the filesystem root.)

#Pike

Pike

int main(){ mv("input.txt", "output.txt"); mv("/input.txt", "/output.txt"); mv("docs", "mydocs"); mv("/docs", "/mydocs"); }

http://rosettacode.org/wiki/Reverse_words_in_a_string

Reverse words in a string

Task Reverse the order of all tokens in each of a number of strings and display the result; the order of characters within a token should not be modified. Example Hey you, Bub! would be shown reversed as: Bub! you, Hey Tokens are any non-space characters separated by spaces (formally, white-space); the visible punctuation form part of the word within which it is located and should not be modified. You may assume that there are no significant non-visible characters in the input. Multiple or superfluous spaces may be compressed into a single space. Some strings have no tokens, so an empty string (or one just containing spaces) would be the result. Display the strings in order (1st, 2nd, 3rd, ···), and one string per line. (You can consider the ten strings as ten lines, and the tokens as words.) Input data (ten lines within the box) line ╔════════════════════════════════════════╗ 1 ║ ---------- Ice and Fire ------------ ║ 2 ║ ║ ◄─── a blank line here. 3 ║ fire, in end will world the say Some ║ 4 ║ ice. in say Some ║ 5 ║ desire of tasted I've what From ║ 6 ║ fire. favor who those with hold I ║ 7 ║ ║ ◄─── a blank line here. 8 ║ ... elided paragraph last ... ║ 9 ║ ║ ◄─── a blank line here. 10 ║ Frost Robert ----------------------- ║ ╚════════════════════════════════════════╝ Cf. Phrase reversals

#OCaml

OCaml

#load "str.cma" let input = ["---------- Ice and Fire ------------"; ""; "fire, in end will world the say Some"; "ice. in say Some"; "desire of tasted I've what From"; "fire. favor who those with hold I"; ""; "... elided paragraph last ..."; ""; "Frost Robert -----------------------"];; let splitted = List.map (Str.split (Str.regexp " ")) input in let reversed = List.map List.rev splitted in let final = List.map (String.concat " ") reversed in List.iter print_endline final;;

http://rosettacode.org/wiki/Rot-13

Rot-13

Task Implement a rot-13 function (or procedure, class, subroutine, or other "callable" object as appropriate to your programming environment). Optionally wrap this function in a utility program (like tr, which acts like a common UNIX utility, performing a line-by-line rot-13 encoding of every line of input contained in each file listed on its command line, or (if no filenames are passed thereon) acting as a filter on its "standard input." (A number of UNIX scripting languages and utilities, such as awk and sed either default to processing files in this way or have command line switches or modules to easily implement these wrapper semantics, e.g., Perl and Python). The rot-13 encoding is commonly known from the early days of Usenet "Netnews" as a way of obfuscating text to prevent casual reading of spoiler or potentially offensive material. Many news reader and mail user agent programs have built-in rot-13 encoder/decoders or have the ability to feed a message through any external utility script for performing this (or other) actions. The definition of the rot-13 function is to simply replace every letter of the ASCII alphabet with the letter which is "rotated" 13 characters "around" the 26 letter alphabet from its normal cardinal position (wrapping around from z to a as necessary). Thus the letters abc become nop and so on. Technically rot-13 is a "mono-alphabetic substitution cipher" with a trivial "key". A proper implementation should work on upper and lower case letters, preserve case, and pass all non-alphabetic characters in the input stream through without alteration. Related tasks Caesar cipher Substitution Cipher Vigenère Cipher/Cryptanalysis Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet

#Slate

Slate

#!/usr/local/bin/slate ch@(String Character traits) rot13 [| value | upper ::= ch isUppercase. value := ch toLowercase as: Integer. (value >= 97) /\ [value < 110] ifTrue: [value += 13] ifFalse: [(value > 109) /\ [value <= 122] ifTrue: [value -= 13]]. upper ifTrue: [(value as: String Character) toUppercase] ifFalse: [value as: String Character] ]. lobby define: #Rot13Encoder &parents: {Encoder}. c@(Rot13Encoder traits) convert [ [c in isAtEnd] whileFalse: [c out nextPut: c in next rot13]. ]. (Rot13Encoder newFrom: Console reader to: Console writer) convert.

http://rosettacode.org/wiki/Roman_numerals/Encode

Roman numerals/Encode

Task Create a function taking a positive integer as its parameter and returning a string containing the Roman numeral representation of that integer. Modern Roman numerals are written by expressing each digit separately, starting with the left most digit and skipping any digit with a value of zero. In Roman numerals: 1990 is rendered: 1000=M, 900=CM, 90=XC; resulting in MCMXC 2008 is written as 2000=MM, 8=VIII; or MMVIII 1666 uses each Roman symbol in descending order: MDCLXVI

#SETL

SETL

examples := [2008, 1666, 1990]; for example in examples loop print( roman_numeral(example) ); end loop; proc roman_numeral( n ); R := [[1000, 'M'], [900, 'CM'], [500, 'D'], [400, 'CD'], [100, 'C'], [90, 'XC'], [50, 'L'], [40, 'XL'], [10, 'X'], [9, 'IX'], [5, 'V'], [4, 'IV'], [1, 'I']]; roman := ''; for numeral in R loop while n >= numeral(1) loop n := n - numeral(1); roman := roman + numeral(2); end loop; end loop; return roman; end;

http://rosettacode.org/wiki/Roman_numerals/Decode

Roman numerals/Decode

Task Create a function that takes a Roman numeral as its argument and returns its value as a numeric decimal integer. You don't need to validate the form of the Roman numeral. Modern Roman numerals are written by expressing each decimal digit of the number to be encoded separately, starting with the leftmost decimal digit and skipping any 0s (zeroes). 1990 is rendered as MCMXC (1000 = M, 900 = CM, 90 = XC) and 2008 is rendered as MMVIII (2000 = MM, 8 = VIII). The Roman numeral for 1666, MDCLXVI, uses each letter in descending order.

#XQuery

XQuery

xquery version "3.1"; declare function local:decode-roman-numeral($roman-numeral as xs:string) { $roman-numeral => upper-case() => for-each( function($roman-numeral-uppercase) { analyze-string($roman-numeral-uppercase, ".")/fn:match ! map { "M": 1000, "D": 500, "C": 100, "L": 50, "X": 10, "V": 5, "I": 1 }(.) } ) => fold-right([0,0], function($number as xs:integer, $accumulator as array(*)) { let $running-total := $accumulator?1 let $previous-number := $accumulator?2 return if ($number lt $previous-number) then [ $running-total - $number, $number ] else [ $running-total + $number, $number ] } ) => array:get(1) }; let $roman-numerals := map { "MCMXCIX": 1999, "MDCLXVI": 1666, "XXV": 25, "XIX": 19, "XI": 11, "CMLIV": 954, "MMXI": 2011, "CD": 400, "MCMXC": 1990, "MMVIII": 2008, "MMIX": 2009, "MMMDCCCLXXXVIII": 3888 } return map:for-each( $roman-numerals, function($roman-numeral, $expected-value) { local:decode-roman-numeral($roman-numeral) eq $expected-value } )

http://rosettacode.org/wiki/Repeat_a_string

Repeat a string

Take a string and repeat it some number of times. Example: repeat("ha", 5) => "hahahahaha" If there is a simpler/more efficient way to repeat a single “character” (i.e. creating a string filled with a certain character), you might want to show that as well (i.e. repeat-char("*", 5) => "*****"). Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet

#Frink

Frink

println[repeat["ha", 5]]

http://rosettacode.org/wiki/Return_multiple_values

Return multiple values

Task Show how to return more than one value from a function.

#PicoLisp

PicoLisp

(de addsub (X Y) (list (+ X Y) (- X Y)) )

http://rosettacode.org/wiki/Return_multiple_values

Return multiple values

Task Show how to return more than one value from a function.

#Pike

Pike

array(int) addsub(int x, int y) { return ({ x+y, x-y }); } [int z, int w] = addsub(5,4);

http://rosettacode.org/wiki/Remove_duplicate_elements

Remove duplicate elements

Sorting Algorithm This is a sorting algorithm. It may be applied to a set of data in order to sort it. For comparing various sorts, see compare sorts. For other sorting algorithms, see sorting algorithms, or: O(n logn) sorts Heap sort | Merge sort | Patience sort | Quick sort O(n log2n) sorts Shell Sort O(n2) sorts Bubble sort | Cocktail sort | Cocktail sort with shifting bounds | Comb sort | Cycle sort | Gnome sort | Insertion sort | Selection sort | Strand sort other sorts Bead sort | Bogo sort | Common sorted list | Composite structures sort | Custom comparator sort | Counting sort | Disjoint sublist sort | External sort | Jort sort | Lexicographical sort | Natural sorting | Order by pair comparisons | Order disjoint list items | Order two numerical lists | Object identifier (OID) sort | Pancake sort | Quickselect | Permutation sort | Radix sort | Ranking methods | Remove duplicate elements | Sleep sort | Stooge sort | [Sort letters of a string] | Three variable sort | Topological sort | Tree sort Given an Array, derive a sequence of elements in which all duplicates are removed. There are basically three approaches seen here: Put the elements into a hash table which does not allow duplicates. The complexity is O(n) on average, and O(n2) worst case. This approach requires a hash function for your type (which is compatible with equality), either built-in to your language, or provided by the user. Sort the elements and remove consecutive duplicate elements. The complexity of the best sorting algorithms is O(n log n). This approach requires that your type be "comparable", i.e., have an ordering. Putting the elements into a self-balancing binary search tree is a special case of sorting. Go through the list, and for each element, check the rest of the list to see if it appears again, and discard it if it does. The complexity is O(n2). The up-shot is that this always works on any type (provided that you can test for equality).

#Erlang

Erlang

List = [1, 2, 3, 2, 2, 4, 5, 5, 4, 6, 6, 5]. UniqueList = gb_sets:to_list(gb_sets:from_list(List)). % Alternatively the builtin: Unique_list = lists:usort( List ).

http://rosettacode.org/wiki/Recaman%27s_sequence

Recaman's sequence

The Recamán's sequence generates Natural numbers. Starting from a(0)=0, the n'th term a(n), where n>0, is the previous term minus n i.e a(n) = a(n-1) - n but only if this is both positive and has not been previousely generated. If the conditions don't hold then a(n) = a(n-1) + n. Task Generate and show here the first 15 members of the sequence. Find and show here, the first duplicated number in the sequence. Optionally: Find and show here, how many terms of the sequence are needed until all the integers 0..1000, inclusive, are generated. References A005132, The On-Line Encyclopedia of Integer Sequences. The Slightly Spooky Recamán Sequence, Numberphile video. Recamán's sequence, on Wikipedia.

#PHP

PHP

<?php $a = array(); array_push($a, 0); $used = array(); array_push($used, 0); $used1000 = array(); array_push($used1000, 0); $foundDup = false; $n = 1; while($n <= 15 || !$foundDup || count($used1000) < 1001) { $next = $a[$n - 1] - $n; if ($next < 1 || in_array($next, $used)) { $next += 2 * $n; } $alreadyUsed = in_array($next, $used); array_push($a, $next); if (!$alreadyUsed) { array_push($used, $next); if (0 <= $next && $next <= 1000) { array_push($used1000, $next); } } if ($n == 14) { echo "The first 15 terms of the Recaman sequence are : ["; foreach($a as $i => $v) { if ( $i == count($a) - 1) echo "$v"; else echo "$v, "; } echo "]\n"; } if (!$foundDup && $alreadyUsed) { printf("The first duplicate term is a[%d] = %d\n", $n, $next); $foundDup = true; } if (count($used1000) == 1001) { printf("Terms up to a[%d] are needed to generate 0 to 1000\n", $n); } $n++; }

http://rosettacode.org/wiki/Reduced_row_echelon_form

Reduced row echelon form

Reduced row echelon form You are encouraged to solve this task according to the task description, using any language you may know. Task Show how to compute the reduced row echelon form (a.k.a. row canonical form) of a matrix. The matrix can be stored in any datatype that is convenient (for most languages, this will probably be a two-dimensional array). Built-in functions or this pseudocode (from Wikipedia) may be used: function ToReducedRowEchelonForm(Matrix M) is lead := 0 rowCount := the number of rows in M columnCount := the number of columns in M for 0 ≤ r < rowCount do if columnCount ≤ lead then stop end if i = r while M[i, lead] = 0 do i = i + 1 if rowCount = i then i = r lead = lead + 1 if columnCount = lead then stop end if end if end while Swap rows i and r If M[r, lead] is not 0 divide row r by M[r, lead] for 0 ≤ i < rowCount do if i ≠ r do Subtract M[i, lead] multiplied by row r from row i end if end for lead = lead + 1 end for end function For testing purposes, the RREF of this matrix: 1 2 -1 -4 2 3 -1 -11 -2 0 -3 22 is: 1 0 0 -8 0 1 0 1 0 0 1 -2

#Icon_and_Unicon

Icon and Unicon

procedure main(A) tM := [[ 1, 2, -1, -4], [ 2, 3, -1,-11], [ -2, 0, -3, 22]] showMat(rref(tM)) end procedure rref(M) lead := 1 rCount := *\M | stop("no Matrix?") cCount := *(M[1]) | 0 every r := !rCount do { i := r while M[i,lead] = 0 do { if (i+:=1) > rCount then { i := r if cCount < (lead +:= 1) then stop("can't reduce") } } M[i] :=: M[r] if 0 ~= (m0 := M[r,lead]) then every !M[r] /:= real(m0) every r ~= (i := !rCount) do { every !(mr := copy(M[r])) *:= M[i,lead] every M[i,j := !cCount] -:= mr[j] } lead +:= 1 } return M end procedure showMat(M) every r := !M do every writes(right(!r,5)||" " | "\n") end

http://rosettacode.org/wiki/Real_constants_and_functions

Real constants and functions

Task Show how to use the following math constants and functions in your language (if not available, note it): e (base of the natural logarithm) π {\displaystyle \pi } square root logarithm (any base allowed) exponential (ex ) absolute value (a.k.a. "magnitude") floor (largest integer less than or equal to this number--not the same as truncate or int) ceiling (smallest integer not less than this number--not the same as round up) power (xy ) Related task Trigonometric Functions

#ERRE

ERRE

PROGRAM R_C_F FUNCTION CEILING(X) CEILING=INT(X)-(X-INT(X)>0) END FUNCTION FUNCTION FLOOR(X) FLOOR=INT(X) END FUNCTION BEGIN PRINT(EXP(1)) ! e not available PRINT(π) ! pi is available or .... PRINT(4*ATN(1)) ! .... equal to X=12.345 Y=1.23 PRINT(SQR(X),X^0.5) ! square root PRINT(LOG(X)) ! natural logarithm base e PRINT(LOG(X)/LOG(10)) ! base 10 logarithm PRINT(LOG(X)/LOG(Y)) ! arbitrary base logarithm (y>0) PRINT(EXP(X)) ! exponential PRINT(ABS(X)) ! absolute value PRINT(FLOOR(X)) ! floor PRINT(CEILING(X)) ! ceiling PRINT(X^Y) ! power END PROGRAM

http://rosettacode.org/wiki/Real_constants_and_functions

Real constants and functions

Task Show how to use the following math constants and functions in your language (if not available, note it): e (base of the natural logarithm) π {\displaystyle \pi } square root logarithm (any base allowed) exponential (ex ) absolute value (a.k.a. "magnitude") floor (largest integer less than or equal to this number--not the same as truncate or int) ceiling (smallest integer not less than this number--not the same as round up) power (xy ) Related task Trigonometric Functions

#F.23

F#

open System let main _ = Console.WriteLine(Math.E); // e Console.WriteLine(Math.PI); // Pi Console.WriteLine(Math.Sqrt(10.0)); // Square Root Console.WriteLine(Math.Log(10.0)); // Logarithm Console.WriteLine(Math.Log10(10.0)); // Base 10 Logarithm Console.WriteLine(Math.Exp(10.0)); // Exponential Console.WriteLine(Math.Abs(10)); // Absolute value Console.WriteLine(Math.Floor(10.0)); // Floor Console.WriteLine(Math.Ceiling(10.0)); // Ceiling Console.WriteLine(Math.Pow(2.0, 5.0)); // Exponentiation 0

http://rosettacode.org/wiki/Remove_lines_from_a_file

Remove lines from a file

Task Remove a specific line or a number of lines from a file. This should be implemented as a routine that takes three parameters (filename, starting line, and the number of lines to be removed). For the purpose of this task, line numbers and the number of lines start at one, so to remove the first two lines from the file foobar.txt, the parameters should be: foobar.txt, 1, 2 Empty lines are considered and should still be counted, and if the specified line is empty, it should still be removed. An appropriate message should appear if an attempt is made to remove lines beyond the end of the file.

#Mathematica.2FWolfram_Language

Mathematica/Wolfram Language

f[doc_String, start_Integer, n_Integer] := Module[{p, newdoc}, p = Import[doc, "List"]; If[start + n - 1 <= Length@p, p = Drop[p, {start, start + n - 1}]; newdoc = FileNameJoin[{DirectoryName[doc], FileBaseName[doc] <> "_removed.txt"}]; Export[newdoc, p, "List"]; , Print["Too few lines in document. Operation aborted."] ] ]

http://rosettacode.org/wiki/Remove_lines_from_a_file

Remove lines from a file

Task Remove a specific line or a number of lines from a file. This should be implemented as a routine that takes three parameters (filename, starting line, and the number of lines to be removed). For the purpose of this task, line numbers and the number of lines start at one, so to remove the first two lines from the file foobar.txt, the parameters should be: foobar.txt, 1, 2 Empty lines are considered and should still be counted, and if the specified line is empty, it should still be removed. An appropriate message should appear if an attempt is made to remove lines beyond the end of the file.

#NewLISP

NewLISP

(context 'ABC) (define (remove-lines-from-a-file filename start num) (setf new-content "") (setf row-counter 0) (setf start-delete-row start) (setf end-delete-row (+ start num -1)) (setf file-content (read-file filename)) (setf max-rows (length (parse file-content "\n" 0))) (cond ((<= start 0) (println "Start line must be >= 1. Value passed: " start)) ((<= num 0) (println "# of lines to remove must be >= 1. Value passed: " num)) ((> start max-rows) (println "Start line must be <= " max-rows ". Value passed: " start)) ((> end-delete-row max-rows) (println "Not so much lines available to be removed. Max " (- max-rows start-delete-row) ". Value passed: " num)) (true (dolist (row (parse file-content "\n" 0)) (++ row-counter) (if (or (< row-counter start-delete-row) (> row-counter end-delete-row)) (setf new-content (append new-content row "\n")) ) ) (write-file filename new-content) ) ) ) (context 'MAIN) (ABC:remove-lines-from-a-file "foobar.txt" 8 3) (exit)

http://rosettacode.org/wiki/Read_entire_file

Read entire file

Task Load the entire contents of some text file as a single string variable. If applicable, discuss: encoding selection, the possibility of memory-mapping. Of course, in practice one should avoid reading an entire file at once if the file is large and the task can be accomplished incrementally instead (in which case check File IO); this is for those cases where having the entire file is actually what is wanted.

#GAP

GAP

InputTextFile("input.txt"); s := ReadAll(f);; # two semicolons to hide the result, which may be long CloseStream(f);

http://rosettacode.org/wiki/Read_entire_file

Read entire file

Task Load the entire contents of some text file as a single string variable. If applicable, discuss: encoding selection, the possibility of memory-mapping. Of course, in practice one should avoid reading an entire file at once if the file is large and the task can be accomplished incrementally instead (in which case check File IO); this is for those cases where having the entire file is actually what is wanted.

#Genie

Genie

[indent=4] /* Read entire file, in Genie valac readEntireFile.gs ./readEntireFile [filename] */ init fileName:string fileContents:string fileName = (args[1] is null) ? "readEntireFile.gs" : args[1] try FileUtils.get_contents(fileName, out fileContents) except exc:Error print "Error: %s", exc.message return stdout.printf("%d bytes read from %s\n", fileContents.length, fileName)

http://rosettacode.org/wiki/Rep-string

Rep-string

Given a series of ones and zeroes in a string, define a repeated string or rep-string as a string which is created by repeating a substring of the first N characters of the string truncated on the right to the length of the input string, and in which the substring appears repeated at least twice in the original. For example, the string 10011001100 is a rep-string as the leftmost four characters of 1001 are repeated three times and truncated on the right to give the original string. Note that the requirement for having the repeat occur two or more times means that the repeating unit is never longer than half the length of the input string. Task Write a function/subroutine/method/... that takes a string and returns an indication of if it is a rep-string and the repeated string. (Either the string that is repeated, or the number of repeated characters would suffice). There may be multiple sub-strings that make a string a rep-string - in that case an indication of all, or the longest, or the shortest would suffice. Use the function to indicate the repeating substring if any, in the following: 1001110011 1110111011 0010010010 1010101010 1111111111 0100101101 0100100 101 11 00 1 Show your output on this page. Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet

#Phixmonti

Phixmonti

include ..\Utilitys.pmt def repstr /# s n -- s #/ "" swap for drop over chain endfor nip enddef def repString /# s -- s #/ len dup var sz 2 / 1 swap 2 tolist for var i 1 i slice var chunk chunk sz i / 1 + repstr 1 sz slice nip over == if chunk exitfor endif endfor len sz == sz 1 == or if ": No repeat string" chain else ": " swap chain chain endif enddef ( "1001110011" "1110111011" "0010010010" "1010101010" "1111111111" "0100101101" "0100100" "101" "11" "00" "1" ) len for get repString print nl endfor

http://rosettacode.org/wiki/Rep-string

Rep-string

Given a series of ones and zeroes in a string, define a repeated string or rep-string as a string which is created by repeating a substring of the first N characters of the string truncated on the right to the length of the input string, and in which the substring appears repeated at least twice in the original. For example, the string 10011001100 is a rep-string as the leftmost four characters of 1001 are repeated three times and truncated on the right to give the original string. Note that the requirement for having the repeat occur two or more times means that the repeating unit is never longer than half the length of the input string. Task Write a function/subroutine/method/... that takes a string and returns an indication of if it is a rep-string and the repeated string. (Either the string that is repeated, or the number of repeated characters would suffice). There may be multiple sub-strings that make a string a rep-string - in that case an indication of all, or the longest, or the shortest would suffice. Use the function to indicate the repeating substring if any, in the following: 1001110011 1110111011 0010010010 1010101010 1111111111 0100101101 0100100 101 11 00 1 Show your output on this page. Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet

#Picat

Picat

go => Strings = [ "1001110011", % 10011 "1110111011", % 1110 "0010010010", % 001 "1010101010", % 1010 "1111111111", % 11111 "0100101101", % no solution "0100100", % 010 "101", % no solution "11", % 1 "00", % 0 "1", % no solution "", % no solution "123123123123123", % 123123 "12312312312312", % 123123 "123123123123124", % no solution "abcabcdabcabcdabc", % abcabcd [1,2,3,4,1,2,3,4,1,2,3] % 1,2,3,4 ], foreach(S in Strings) printf("%w: ", S), if maxrep(S,Substr,N) then println([substr=Substr,n=N]) else println("no solution") end end, nl. % the largest repeating substring maxrep(S,Substr,N) => maxof(rep(S,Substr,N),N). rep(S,Substr,N) => between(1,S.length div 2, N), Len = S.length, Len2 = Len - (Len mod N), Substr = slice(S,1,N), % count the number of proper slices SS = [1 : I in 1..N..Len2, slice(S,I,I+N-1) = Substr], SS.length = Len div N, % the last (truncated) slice (or []) must be a substring of Substr Rest = slice(S,Len2+1,Len), find(Substr,Rest,1,_).

http://rosettacode.org/wiki/Regular_expressions

Regular expressions

Task match a string against a regular expression substitute part of a string using a regular expression

#ooRexx

ooRexx

/* Rexx */ /* Using the RxRegExp Regular Expression built-in utility class */ st1 = 'Fee, fie, foe, fum, I smell the blood of an Englishman' rx1 = '[Ff]?e' -- unlike most regex engines, RxRegExp uses '?' instead of '.' to match any single character sbx = 'foo' myRE = .RegularExpression~new() myRE~parse(rx1, MINIMAL) mcm = myRE~pos(st1) say 'String "'st1'"' 'matches pattern "'rx1'":' bool2string(mcm > 0) say -- The RxRegExp package doesn't provide a replace capability so you must roll your own st0 = st1 loop label GREP forever mcp = myRE~pos(st1) if mcp > 0 then do mpp = myRE~position fnd = st1~substr(mcp, mpp - mcp + 1) stx = st1~changestr(fnd, sbx, 1) end else leave GREP st1 = stx end GREP say 'Input string: "'st0'"' say 'Result string: "'stx'"' return exit bool2string: procedure do parse arg bv . if bv then bx = 'true' else bx = 'false' return bx end exit ::requires "rxregexp.cls"

http://rosettacode.org/wiki/Reverse_a_string

Reverse a string

Task Take a string and reverse it. For example, "asdf" becomes "fdsa". Extra credit Preserve Unicode combining characters. For example, "as⃝df̅" becomes "f̅ds⃝a", not "̅fd⃝sa". Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet

#COBOL

COBOL

FUNCTION REVERSE('QWERTY')

http://rosettacode.org/wiki/Repeat

Repeat

Task Write a procedure which accepts as arguments another procedure and a positive integer. The latter procedure is executed a number of times equal to the accepted integer.

#Tcl

Tcl

proc repeat {command count} { for {set i 0} {$i < $count} {incr i} { uplevel 1 $command } } proc example {} {puts "This is an example"} repeat example 4

http://rosettacode.org/wiki/Repeat

Repeat

Task Write a procedure which accepts as arguments another procedure and a positive integer. The latter procedure is executed a number of times equal to the accepted integer.

#uBasic.2F4tH

uBasic/4tH

Proc _Repeat (_HelloWorld, 5) : End _Repeat Param (2) : Local (1) : For c@ = 1 To b@ : Proc a@ : Next : Return _HelloWorld Print "Hello world!" : Return

http://rosettacode.org/wiki/Rename_a_file

Rename a file

Task Rename: a file called input.txt into output.txt and a directory called docs into mydocs. This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root. It can be assumed that the user has the rights to do so. (In unix-type systems, only the user root would have sufficient permissions in the filesystem root.)

#Pop11

Pop11

sys_file_move('inputs.txt', 'output.txt'); sys_file_move('docs', 'mydocs'); sys_file_move('/inputs.txt', '/output.txt'); sys_file_move(/'docs', '/mydocs');

http://rosettacode.org/wiki/Rename_a_file

Rename a file

Task Rename: a file called input.txt into output.txt and a directory called docs into mydocs. This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root. It can be assumed that the user has the rights to do so. (In unix-type systems, only the user root would have sufficient permissions in the filesystem root.)

#PowerShell

PowerShell

Rename-Item input.txt output.txt # The Rename-item has the alias ren ren input.txt output.txt

http://rosettacode.org/wiki/Reverse_words_in_a_string

Reverse words in a string

Task Reverse the order of all tokens in each of a number of strings and display the result; the order of characters within a token should not be modified. Example Hey you, Bub! would be shown reversed as: Bub! you, Hey Tokens are any non-space characters separated by spaces (formally, white-space); the visible punctuation form part of the word within which it is located and should not be modified. You may assume that there are no significant non-visible characters in the input. Multiple or superfluous spaces may be compressed into a single space. Some strings have no tokens, so an empty string (or one just containing spaces) would be the result. Display the strings in order (1st, 2nd, 3rd, ···), and one string per line. (You can consider the ten strings as ten lines, and the tokens as words.) Input data (ten lines within the box) line ╔════════════════════════════════════════╗ 1 ║ ---------- Ice and Fire ------------ ║ 2 ║ ║ ◄─── a blank line here. 3 ║ fire, in end will world the say Some ║ 4 ║ ice. in say Some ║ 5 ║ desire of tasted I've what From ║ 6 ║ fire. favor who those with hold I ║ 7 ║ ║ ◄─── a blank line here. 8 ║ ... elided paragraph last ... ║ 9 ║ ║ ◄─── a blank line here. 10 ║ Frost Robert ----------------------- ║ ╚════════════════════════════════════════╝ Cf. Phrase reversals

#Oforth

Oforth

: revWords(s) s words reverse unwords ; : reverseWords "---------- Ice and Fire ------------" revWords println " " revWords println "fire, in end will world the say Some" revWords println "ice. in say Some " revWords println "desire of tasted I've what From " revWords println "fire. favor who those with hold I " revWords println " " revWords println "... elided paragraph last ... " revWords println " " revWords println "Frost Robert -----------------------" revWords println ;

http://rosettacode.org/wiki/Reverse_words_in_a_string

Reverse words in a string

Task Reverse the order of all tokens in each of a number of strings and display the result; the order of characters within a token should not be modified. Example Hey you, Bub! would be shown reversed as: Bub! you, Hey Tokens are any non-space characters separated by spaces (formally, white-space); the visible punctuation form part of the word within which it is located and should not be modified. You may assume that there are no significant non-visible characters in the input. Multiple or superfluous spaces may be compressed into a single space. Some strings have no tokens, so an empty string (or one just containing spaces) would be the result. Display the strings in order (1st, 2nd, 3rd, ···), and one string per line. (You can consider the ten strings as ten lines, and the tokens as words.) Input data (ten lines within the box) line ╔════════════════════════════════════════╗ 1 ║ ---------- Ice and Fire ------------ ║ 2 ║ ║ ◄─── a blank line here. 3 ║ fire, in end will world the say Some ║ 4 ║ ice. in say Some ║ 5 ║ desire of tasted I've what From ║ 6 ║ fire. favor who those with hold I ║ 7 ║ ║ ◄─── a blank line here. 8 ║ ... elided paragraph last ... ║ 9 ║ ║ ◄─── a blank line here. 10 ║ Frost Robert ----------------------- ║ ╚════════════════════════════════════════╝ Cf. Phrase reversals

#Pascal

Pascal

program Reverse_words(Output); {$H+} const nl = chr(10); // Linefeed sp = chr(32); // Space TXT = '---------- Ice and Fire -----------'+nl+ nl+ 'fire, in end will world the say Some'+nl+ 'ice. in say Some'+nl+ 'desire of tasted I''ve what From'+nl+ 'fire. favor who those with hold I'+nl+ nl+ '... elided paragraph last ...'+nl+ nl+ 'Frost Robert -----------------------'+nl; var I : integer; ew, lw : ansistring; c : char; function addW : ansistring; var r : ansistring = ''; begin r := ew + sp + lw; ew := ''; addW := r end; begin ew := ''; lw := ''; for I := 1 to strlen(TXT) do begin c := TXT[I]; case c of sp : lw := addW; nl : begin writeln(addW); lw := '' end; else ew := ew + c end; end; readln; end.

http://rosettacode.org/wiki/Rot-13

Rot-13

Task Implement a rot-13 function (or procedure, class, subroutine, or other "callable" object as appropriate to your programming environment). Optionally wrap this function in a utility program (like tr, which acts like a common UNIX utility, performing a line-by-line rot-13 encoding of every line of input contained in each file listed on its command line, or (if no filenames are passed thereon) acting as a filter on its "standard input." (A number of UNIX scripting languages and utilities, such as awk and sed either default to processing files in this way or have command line switches or modules to easily implement these wrapper semantics, e.g., Perl and Python). The rot-13 encoding is commonly known from the early days of Usenet "Netnews" as a way of obfuscating text to prevent casual reading of spoiler or potentially offensive material. Many news reader and mail user agent programs have built-in rot-13 encoder/decoders or have the ability to feed a message through any external utility script for performing this (or other) actions. The definition of the rot-13 function is to simply replace every letter of the ASCII alphabet with the letter which is "rotated" 13 characters "around" the 26 letter alphabet from its normal cardinal position (wrapping around from z to a as necessary). Thus the letters abc become nop and so on. Technically rot-13 is a "mono-alphabetic substitution cipher" with a trivial "key". A proper implementation should work on upper and lower case letters, preserve case, and pass all non-alphabetic characters in the input stream through without alteration. Related tasks Caesar cipher Substitution Cipher Vigenère Cipher/Cryptanalysis Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet

#Smalltalk

Smalltalk

"1. simple approach" rot13 := [ :string | string collect: [ :each | | index | index := 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ' indexOf: each ifAbsent: [ 0 ]. "Smalltalk uses 1-based indexing" index isZero ifTrue: [ each ] ifFalse: [ 'nopqrstuvwxyzabcdefghijklmNOPQRSTUVWXYZABCDEFGHIJKLM' at: index ] ] ]. (rot13 value: 'Test123') printNl "gives 'Grfg123'" "2. extending built-in classes" Character extend [ + inc [ (inc isKindOf: Character) ifTrue: [ ^ ( Character value: ((self asInteger) + (inc asInteger)) ) ] ifFalse: [ ^ ( Character value: ((self asInteger) + inc) ) ] ] - inc [ ^ ( self + (inc asInteger negated) ) ] trFrom: map1 to: map2 [ (map1 includes: self) ifTrue: [ ^ map2 at: (map1 indexOf: self) ] ifFalse: [ ^self ] ] ]. String extend [ rot: num [ |s| s := String new. self do: [ :c | ((c asLowercase) between: $a and: $z) ifTrue: [ |c1| c1 := ( $a + ((((c asLowercase) - $a + num) asInteger) rem:26)). (c isLowercase) ifFalse: [ c1 := c1 asUppercase ]. s := s, (c1 asString) ] ifFalse: [ s := s, (c asString) ] ]. ^s ] ]. ('abcdefghijklmnopqrstuvwxyz123!' rot: 13) displayNl. (('abcdefghijklmnopqrstuvwxyz123!' rot: 13) rot: 13) displayNl. "2. using a 'translation'. Not very idiomatic Smalltalk code" rotThirteen := [ :s | |m1 m2 r| r := String new. m1 := OrderedCollection new. 0 to: 25 do: [ :i | m1 add: ($a + i) ]. m2 := OrderedCollection new. 0 to: 25 do: [ :i | m2 add: ($a + ((i+13) rem: 26)) ]. s do: [ :c | (c between: $a and: $z) | (c between: $A and: $Z) ifTrue: [ | a | a := (c asLowercase) trFrom: m1 to: m2. (c isUppercase) ifTrue: [ a := a asUppercase ]. r := r, (a asString)] ifFalse: [ r := r, (c asString) ] ]. r ]. (rotThirteen value: 'abcdefghijklmnopqrstuvwxyz123!') displayNl.

http://rosettacode.org/wiki/Roman_numerals/Encode

Roman numerals/Encode

Task Create a function taking a positive integer as its parameter and returning a string containing the Roman numeral representation of that integer. Modern Roman numerals are written by expressing each digit separately, starting with the left most digit and skipping any digit with a value of zero. In Roman numerals: 1990 is rendered: 1000=M, 900=CM, 90=XC; resulting in MCMXC 2008 is written as 2000=MM, 8=VIII; or MMVIII 1666 uses each Roman symbol in descending order: MDCLXVI

#Shen

Shen

(define encodeGlyphs ACC 0 _ -> ACC ACC N [Glyph Value | Rest] -> (encodeGlyphs (@s ACC Glyph) (- N Value) [Glyph Value | Rest]) where (>= N Value) ACC N [Glyph Value | Rest] -> (encodeGlyphs ACC N Rest) ) (define encodeRoman N -> (encodeGlyphs "" N ["M" 1000 "CM" 900 "D" 500 "CD" 400 "C" 100 "XC" 90 "L" 50 "XL" 40 "X" 10 "IX" 9 "V" 5 "IV" 4 "I" 1]) )

http://rosettacode.org/wiki/Roman_numerals/Decode

Roman numerals/Decode

Task Create a function that takes a Roman numeral as its argument and returns its value as a numeric decimal integer. You don't need to validate the form of the Roman numeral. Modern Roman numerals are written by expressing each decimal digit of the number to be encoded separately, starting with the leftmost decimal digit and skipping any 0s (zeroes). 1990 is rendered as MCMXC (1000 = M, 900 = CM, 90 = XC) and 2008 is rendered as MMVIII (2000 = MM, 8 = VIII). The Roman numeral for 1666, MDCLXVI, uses each letter in descending order.

#Yabasic

Yabasic

romans$ = "MDCLXVI" decmls$ = "1000,500,100,50,10,5,1" sub romanDec(s$) local i, n, prev, res, decmls$(1) n = token(decmls$, decmls$(), ",") for i = len(s$) to 1 step -1 n = val(decmls$(instr(romans$, mid$(s$, i, 1)))) if n < prev n = 0 - n res = res + n prev = n next i return res end sub ? romanDec("MCMXCIX") // 1999 ? romanDec("MDCLXVI") // 1666 ? romanDec("XXV") // 25 ? romanDec("XIX") // 19 ? romanDec("XI") // 11 ? romanDec("CMLIV") // 954 ? romanDec("MMXI") // 2011 ? romanDec("CD") // 400 ? romanDec("MCMXC") // 1990 ? romanDec("MMVIII") // 2008 ? romanDec("MMIX") // 2009 ? romanDec("MDCLXVI") // 1666 ? romanDec("MMMDCCCLXXXVIII") // 3888

http://rosettacode.org/wiki/Repeat_a_string

Repeat a string

Take a string and repeat it some number of times. Example: repeat("ha", 5) => "hahahahaha" If there is a simpler/more efficient way to repeat a single “character” (i.e. creating a string filled with a certain character), you might want to show that as well (i.e. repeat-char("*", 5) => "*****"). Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet

#Gambas

Gambas

Public Sub Main() Print String$(5, "ha") End

http://rosettacode.org/wiki/Return_multiple_values

Return multiple values

Task Show how to return more than one value from a function.

#PL.2FI

PL/I

define structure 1 h, 2 a (10) float; declare i fixed binary; sub: procedure (a, b) returns (type(h)); declare (a, b) float; declare p type (h); do i = 1 to 10; p.a(i) = i; end; return (p); end sub;

http://rosettacode.org/wiki/Return_multiple_values

Return multiple values

Task Show how to return more than one value from a function.

#Plain_English

Plain English

To run: Start up. Compute a product and a quotient given 15 and 3. Write "The product is " then the product on the console. Write "The quotient is " then the quotient on the console. Wait for the escape key. Shut down. A product is a number. To compute a product and a quotient given a number and another number: Put the number times the other number into the product. Put the number divided by the other number into the quotient.

http://rosettacode.org/wiki/Remove_duplicate_elements

Remove duplicate elements

Sorting Algorithm This is a sorting algorithm. It may be applied to a set of data in order to sort it. For comparing various sorts, see compare sorts. For other sorting algorithms, see sorting algorithms, or: O(n logn) sorts Heap sort | Merge sort | Patience sort | Quick sort O(n log2n) sorts Shell Sort O(n2) sorts Bubble sort | Cocktail sort | Cocktail sort with shifting bounds | Comb sort | Cycle sort | Gnome sort | Insertion sort | Selection sort | Strand sort other sorts Bead sort | Bogo sort | Common sorted list | Composite structures sort | Custom comparator sort | Counting sort | Disjoint sublist sort | External sort | Jort sort | Lexicographical sort | Natural sorting | Order by pair comparisons | Order disjoint list items | Order two numerical lists | Object identifier (OID) sort | Pancake sort | Quickselect | Permutation sort | Radix sort | Ranking methods | Remove duplicate elements | Sleep sort | Stooge sort | [Sort letters of a string] | Three variable sort | Topological sort | Tree sort Given an Array, derive a sequence of elements in which all duplicates are removed. There are basically three approaches seen here: Put the elements into a hash table which does not allow duplicates. The complexity is O(n) on average, and O(n2) worst case. This approach requires a hash function for your type (which is compatible with equality), either built-in to your language, or provided by the user. Sort the elements and remove consecutive duplicate elements. The complexity of the best sorting algorithms is O(n log n). This approach requires that your type be "comparable", i.e., have an ordering. Putting the elements into a self-balancing binary search tree is a special case of sorting. Go through the list, and for each element, check the rest of the list to see if it appears again, and discard it if it does. The complexity is O(n2). The up-shot is that this always works on any type (provided that you can test for equality).

#Euphoria

Euphoria

include sort.e function uniq(sequence s) sequence out s = sort(s) out = s[1..1] for i = 2 to length(s) do if not equal(s[i],out[$]) then out = append(out, s[i]) end if end for return out end function constant s = {1, 2, 1, 4, 5, 2, 15, 1, 3, 4} ? s ? uniq(s)

http://rosettacode.org/wiki/Recaman%27s_sequence

Recaman's sequence

The Recamán's sequence generates Natural numbers. Starting from a(0)=0, the n'th term a(n), where n>0, is the previous term minus n i.e a(n) = a(n-1) - n but only if this is both positive and has not been previousely generated. If the conditions don't hold then a(n) = a(n-1) + n. Task Generate and show here the first 15 members of the sequence. Find and show here, the first duplicated number in the sequence. Optionally: Find and show here, how many terms of the sequence are needed until all the integers 0..1000, inclusive, are generated. References A005132, The On-Line Encyclopedia of Integer Sequences. The Slightly Spooky Recamán Sequence, Numberphile video. Recamán's sequence, on Wikipedia.

#PL.2FI

PL/I

recaman: procedure options(main); declare A(0:30) fixed; /* is X in the first N terms of the Recaman sequence? */ find: procedure(x, n) returns(bit); declare (x, n, i) fixed; do i=0 to n-1; if A(i)=x then return('1'b); end; return('0'b); end find; /* generate the N'th term of the Recaman sequence */ generate: procedure(n) returns(fixed); declare n fixed; if n=0 then A(0) = 0; else do; declare (sub, add) fixed; sub = A(n-1) - n; add = A(n-1) + n; /* A(n-1) - n not positive? */ if sub <= 0 then A(n) = add; /* A(n-1) - n already generated? */ else if find(sub, n) then A(n) = add; else A(n) = sub; end; return(A(n)); end generate; declare i fixed; put skip list('First 15 members:'); do i=0 to 14; put edit(generate(i)) (F(3)); end; put skip list('First repeated term: '); do i=15 repeat(i+1) while(^find(generate(i), i)); end; put edit('A(',i,') = ',A(i)) (A,F(2),A,F(2)); end recaman;

http://rosettacode.org/wiki/Reduced_row_echelon_form

Reduced row echelon form

Reduced row echelon form You are encouraged to solve this task according to the task description, using any language you may know. Task Show how to compute the reduced row echelon form (a.k.a. row canonical form) of a matrix. The matrix can be stored in any datatype that is convenient (for most languages, this will probably be a two-dimensional array). Built-in functions or this pseudocode (from Wikipedia) may be used: function ToReducedRowEchelonForm(Matrix M) is lead := 0 rowCount := the number of rows in M columnCount := the number of columns in M for 0 ≤ r < rowCount do if columnCount ≤ lead then stop end if i = r while M[i, lead] = 0 do i = i + 1 if rowCount = i then i = r lead = lead + 1 if columnCount = lead then stop end if end if end while Swap rows i and r If M[r, lead] is not 0 divide row r by M[r, lead] for 0 ≤ i < rowCount do if i ≠ r do Subtract M[i, lead] multiplied by row r from row i end if end for lead = lead + 1 end for end function For testing purposes, the RREF of this matrix: 1 2 -1 -4 2 3 -1 -11 -2 0 -3 22 is: 1 0 0 -8 0 1 0 1 0 0 1 -2

#J

J

NB.*pivot v Pivot at row, column NB. form: (row,col) pivot M pivot=: dyad define 'r c'=. x col=. c{"1 y y - (col - r = i.#y) */ (r{y) % r{col ) NB.*gauss_jordan v Gauss-Jordan elimination (full pivoting) NB. y is: matrix NB. x is: optional minimum tolerance, default 1e_15. NB. If a column below the current pivot has numbers of magnitude all NB. less then x, it is treated as all zeros. gauss_jordan=: verb define 1e_15 gauss_jordan y : mtx=. y 'r c'=. $mtx rows=. i.r i=. j=. 0 max=. i.>./ while. (i<r) *. j<c do. k=. max col=. | i}. j{"1 mtx if. 0 < x-k{col do. NB. if all col < tol, set to 0: mtx=. 0 (<(i}.rows);j) } mtx else. NB. otherwise sort and pivot: if. k do. mtx=. (<i,i+k) C. mtx end. mtx=. (i,j) pivot mtx i=. >:i end. j=. >:j end. mtx )

http://rosettacode.org/wiki/Real_constants_and_functions

Real constants and functions

Task Show how to use the following math constants and functions in your language (if not available, note it): e (base of the natural logarithm) π {\displaystyle \pi } square root logarithm (any base allowed) exponential (ex ) absolute value (a.k.a. "magnitude") floor (largest integer less than or equal to this number--not the same as truncate or int) ceiling (smallest integer not less than this number--not the same as round up) power (xy ) Related task Trigonometric Functions

#Factor

Factor

e ! e pi ! π sqrt ! square root log ! natural logarithm exp ! exponentiation abs ! absolute value floor ! greatest whole number smaller than or equal ceiling ! smallest whole number greater than or equal truncate ! remove the fractional part (i.e. round towards 0) round ! round to next whole number ^ ! power

http://rosettacode.org/wiki/Real_constants_and_functions

Real constants and functions

Task Show how to use the following math constants and functions in your language (if not available, note it): e (base of the natural logarithm) π {\displaystyle \pi } square root logarithm (any base allowed) exponential (ex ) absolute value (a.k.a. "magnitude") floor (largest integer less than or equal to this number--not the same as truncate or int) ceiling (smallest integer not less than this number--not the same as round up) power (xy ) Related task Trigonometric Functions

#Fantom

Fantom

Float.e Float.pi 9f.sqrt 9f.log // natural logarithm 9f.log10 // logarithm to base 10 9f.exp // exponentiation (-3f).abs // absolute value, note bracket 3.2f.floor // nearest Int smaller than this number 3.2f.ceil // nearest Int bigger than this number 3.2f.round // nearest Int 3f.pow(2f) // power

http://rosettacode.org/wiki/Remove_lines_from_a_file

Remove lines from a file

Task Remove a specific line or a number of lines from a file. This should be implemented as a routine that takes three parameters (filename, starting line, and the number of lines to be removed). For the purpose of this task, line numbers and the number of lines start at one, so to remove the first two lines from the file foobar.txt, the parameters should be: foobar.txt, 1, 2 Empty lines are considered and should still be counted, and if the specified line is empty, it should still be removed. An appropriate message should appear if an attempt is made to remove lines beyond the end of the file.

#Nim

Nim

import sequtils, strutils proc removeLines*(filename: string; start, count: Positive) = # Read the whole file, split into lines but keep the ends of line. var lines = filename.readFile().splitLines(keepEol = true) # Remove final empty string if any. if lines[^1].len == 0: lines.setLen(lines.len - 1) # Compute indices and check validity. let first = start - 1 let last = first + count - 1 if last >= lines.len: raise newException(IOError, "trying to delete lines after end of file.") # Delete the lines and write the file. lines.delete(first, last) filename.writeFile(lines.join())

http://rosettacode.org/wiki/Remove_lines_from_a_file

Remove lines from a file

Task Remove a specific line or a number of lines from a file. This should be implemented as a routine that takes three parameters (filename, starting line, and the number of lines to be removed). For the purpose of this task, line numbers and the number of lines start at one, so to remove the first two lines from the file foobar.txt, the parameters should be: foobar.txt, 1, 2 Empty lines are considered and should still be counted, and if the specified line is empty, it should still be removed. An appropriate message should appear if an attempt is made to remove lines beyond the end of the file.

#OCaml

OCaml

let input_line_opt ic = try Some (input_line ic) with End_of_file -> None let delete_lines filename start skip = if start < 1 || skip < 1 then invalid_arg "delete_lines"; let tmp_file = filename ^ ".tmp" in let ic = open_in filename and oc = open_out tmp_file in let until = start + skip - 1 in let rec aux i = match input_line_opt ic with | Some line -> if i < start || i > until then (output_string oc line; output_char oc '\n'); aux (succ i) | None -> close_in ic; close_out oc; Sys.remove filename; Sys.rename tmp_file filename in aux 1 let usage () = Printf.printf "Usage:\n%s <filename> <startline> <skipnumber>\n" Sys.argv.(0); exit 0 let () = if Array.length Sys.argv < 4 then usage (); delete_lines Sys.argv.(1) (int_of_string Sys.argv.(2)) (int_of_string Sys.argv.(3))

http://rosettacode.org/wiki/Read_entire_file

Read entire file

Task Load the entire contents of some text file as a single string variable. If applicable, discuss: encoding selection, the possibility of memory-mapping. Of course, in practice one should avoid reading an entire file at once if the file is large and the task can be accomplished incrementally instead (in which case check File IO); this is for those cases where having the entire file is actually what is wanted.

#Go

Go

import "io/ioutil" data, err := ioutil.ReadFile(filename) sv := string(data)

http://rosettacode.org/wiki/Read_entire_file

Read entire file

Task Load the entire contents of some text file as a single string variable. If applicable, discuss: encoding selection, the possibility of memory-mapping. Of course, in practice one should avoid reading an entire file at once if the file is large and the task can be accomplished incrementally instead (in which case check File IO); this is for those cases where having the entire file is actually what is wanted.

#Groovy

Groovy

def fileContent = new File("c:\\file.txt").text

http://rosettacode.org/wiki/Rep-string

Rep-string

Given a series of ones and zeroes in a string, define a repeated string or rep-string as a string which is created by repeating a substring of the first N characters of the string truncated on the right to the length of the input string, and in which the substring appears repeated at least twice in the original. For example, the string 10011001100 is a rep-string as the leftmost four characters of 1001 are repeated three times and truncated on the right to give the original string. Note that the requirement for having the repeat occur two or more times means that the repeating unit is never longer than half the length of the input string. Task Write a function/subroutine/method/... that takes a string and returns an indication of if it is a rep-string and the repeated string. (Either the string that is repeated, or the number of repeated characters would suffice). There may be multiple sub-strings that make a string a rep-string - in that case an indication of all, or the longest, or the shortest would suffice. Use the function to indicate the repeating substring if any, in the following: 1001110011 1110111011 0010010010 1010101010 1111111111 0100101101 0100100 101 11 00 1 Show your output on this page. Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet

#PicoLisp

PicoLisp

(de repString (Str) (let Lst (chop Str) (for (N (/ (length Lst) 2) (gt0 N) (dec N)) (T (use (Lst X) (let H (cut N 'Lst) (loop (setq X (cut N 'Lst)) (NIL (head X H)) (NIL Lst T) ) ) ) N ) ) ) )

http://rosettacode.org/wiki/Rep-string

Rep-string

Given a series of ones and zeroes in a string, define a repeated string or rep-string as a string which is created by repeating a substring of the first N characters of the string truncated on the right to the length of the input string, and in which the substring appears repeated at least twice in the original. For example, the string 10011001100 is a rep-string as the leftmost four characters of 1001 are repeated three times and truncated on the right to give the original string. Note that the requirement for having the repeat occur two or more times means that the repeating unit is never longer than half the length of the input string. Task Write a function/subroutine/method/... that takes a string and returns an indication of if it is a rep-string and the repeated string. (Either the string that is repeated, or the number of repeated characters would suffice). There may be multiple sub-strings that make a string a rep-string - in that case an indication of all, or the longest, or the shortest would suffice. Use the function to indicate the repeating substring if any, in the following: 1001110011 1110111011 0010010010 1010101010 1111111111 0100101101 0100100 101 11 00 1 Show your output on this page. Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet

#PL.2FI

PL/I

rep: procedure options (main); /* 5 May 2015 */ declare s bit (10) varying; declare (i, k) fixed binary; main_loop: do s = '1001110011'b, '1110111011'b, '0010010010'b, '1010101010'b, '1111111111'b, '0100101101'b, '0100100'b, '101'b, '11'b, '00'b, '1'b; k = length(s); do i = k/2 to 1 by -1; if substr(s, 1, i) = substr(s, i+1, i) then do; put skip edit (s, ' is a rep-string containing ', substr(s, 1, i) ) (a); iterate main_loop; end; end; put skip edit (s, ' is not a rep-string') (a); end; end rep;

http://rosettacode.org/wiki/Regular_expressions

Regular expressions

Task match a string against a regular expression substitute part of a string using a regular expression

#Oxygene

Oxygene

// Match and Replace part of a string using a Regular Expression // // Nigel Galloway - April 15th., 2012 // namespace re; interface type re = class public class method Main; end; implementation class method re.Main; const myString = 'I think that I am Nigel'; var r: System.Text.RegularExpressions.Regex; myResult : String; begin r := new System.Text.RegularExpressions.Regex('(I am)|(you are)'); Console.WriteLine("{0} contains {1}", myString, r.Match(myString)); myResult := r.Replace(myString, "you are"); Console.WriteLine("{0} contains {1}", myResult, r.Match(myResult)); end; end.

http://rosettacode.org/wiki/Reverse_a_string

Reverse a string

Task Take a string and reverse it. For example, "asdf" becomes "fdsa". Extra credit Preserve Unicode combining characters. For example, "as⃝df̅" becomes "f̅ds⃝a", not "̅fd⃝sa". Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet

#CoffeeScript

CoffeeScript

"qwerty".split("").reverse().join ""

http://rosettacode.org/wiki/Repeat

Repeat

Task Write a procedure which accepts as arguments another procedure and a positive integer. The latter procedure is executed a number of times equal to the accepted integer.

#Ursa

Ursa

def repeat (function f, int n) for (set n n) (> n 0) (dec n) f end for end repeat def procedure () out "Hello! " console end procedure # outputs "Hello! " 5 times repeat procedure 5

http://rosettacode.org/wiki/Repeat

Repeat

Task Write a procedure which accepts as arguments another procedure and a positive integer. The latter procedure is executed a number of times equal to the accepted integer.

#VBA

VBA

Private Sub Repeat(rid As String, n As Integer) For i = 1 To n Application.Run rid Next i End Sub Private Sub Hello() Debug.Print "Hello" End Sub Public Sub main() Repeat "Hello", 5 End Sub

http://rosettacode.org/wiki/Rename_a_file

Rename a file

Task Rename: a file called input.txt into output.txt and a directory called docs into mydocs. This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root. It can be assumed that the user has the rights to do so. (In unix-type systems, only the user root would have sufficient permissions in the filesystem root.)

#Processing

Processing

void setup(){ boolean sketchfile = rename(sketchPath("input.txt"), sketchPath("output.txt")); boolean sketchfold = rename(sketchPath("docs"), sketchPath("mydocs")); // sketches will seldom have write permission to root files/folders boolean rootfile = rename("input.txt", "output.txt"); boolean rootfold = rename("docs", "mydocs"); // true if succeeded, false if failed println(sketchfile, sketchfold, rootfile, rootfold); } boolean rename(String oldname, String newname) { // File (or directory) with old name File file = new File(oldname); // File (or directory) with new name File file2 = new File(newname); // Rename file (or directory) boolean success = file.renameTo(file2); return success; }

http://rosettacode.org/wiki/Rename_a_file

Rename a file

Task Rename: a file called input.txt into output.txt and a directory called docs into mydocs. This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root. It can be assumed that the user has the rights to do so. (In unix-type systems, only the user root would have sufficient permissions in the filesystem root.)

#ProDOS

ProDOS

rename input.txt to output.txt rename docs to mydocs

http://rosettacode.org/wiki/Reverse_words_in_a_string

Reverse words in a string

Task Reverse the order of all tokens in each of a number of strings and display the result; the order of characters within a token should not be modified. Example Hey you, Bub! would be shown reversed as: Bub! you, Hey Tokens are any non-space characters separated by spaces (formally, white-space); the visible punctuation form part of the word within which it is located and should not be modified. You may assume that there are no significant non-visible characters in the input. Multiple or superfluous spaces may be compressed into a single space. Some strings have no tokens, so an empty string (or one just containing spaces) would be the result. Display the strings in order (1st, 2nd, 3rd, ···), and one string per line. (You can consider the ten strings as ten lines, and the tokens as words.) Input data (ten lines within the box) line ╔════════════════════════════════════════╗ 1 ║ ---------- Ice and Fire ------------ ║ 2 ║ ║ ◄─── a blank line here. 3 ║ fire, in end will world the say Some ║ 4 ║ ice. in say Some ║ 5 ║ desire of tasted I've what From ║ 6 ║ fire. favor who those with hold I ║ 7 ║ ║ ◄─── a blank line here. 8 ║ ... elided paragraph last ... ║ 9 ║ ║ ◄─── a blank line here. 10 ║ Frost Robert ----------------------- ║ ╚════════════════════════════════════════╝ Cf. Phrase reversals

#Perl

Perl

print join(" ", reverse split), "\n" for <DATA>; __DATA__ ---------- Ice and Fire ------------ fire, in end will world the say Some ice. in say Some desire of tasted I've what From fire. favor who those with hold I ... elided paragraph last ... Frost Robert -----------------------

http://rosettacode.org/wiki/Reverse_words_in_a_string

Reverse words in a string

Task Reverse the order of all tokens in each of a number of strings and display the result; the order of characters within a token should not be modified. Example Hey you, Bub! would be shown reversed as: Bub! you, Hey Tokens are any non-space characters separated by spaces (formally, white-space); the visible punctuation form part of the word within which it is located and should not be modified. You may assume that there are no significant non-visible characters in the input. Multiple or superfluous spaces may be compressed into a single space. Some strings have no tokens, so an empty string (or one just containing spaces) would be the result. Display the strings in order (1st, 2nd, 3rd, ···), and one string per line. (You can consider the ten strings as ten lines, and the tokens as words.) Input data (ten lines within the box) line ╔════════════════════════════════════════╗ 1 ║ ---------- Ice and Fire ------------ ║ 2 ║ ║ ◄─── a blank line here. 3 ║ fire, in end will world the say Some ║ 4 ║ ice. in say Some ║ 5 ║ desire of tasted I've what From ║ 6 ║ fire. favor who those with hold I ║ 7 ║ ║ ◄─── a blank line here. 8 ║ ... elided paragraph last ... ║ 9 ║ ║ ◄─── a blank line here. 10 ║ Frost Robert ----------------------- ║ ╚════════════════════════════════════════╝ Cf. Phrase reversals

#Phix

Phix

with javascript_semantics constant test=""" ---------- Ice and Fire ------------ fire, in end will world the say Some ice. in say Some desire of tasted I've what From fire. favor who those with hold I ... elided paragraph last ... Frost Robert ----------------------- """ sequence lines = split(test,'\n') for i=1 to length(lines) do lines[i] = join(reverse(split(lines[i]))) end for puts(1,join(lines,"\n"))

http://rosettacode.org/wiki/Rot-13

Rot-13

Task Implement a rot-13 function (or procedure, class, subroutine, or other "callable" object as appropriate to your programming environment). Optionally wrap this function in a utility program (like tr, which acts like a common UNIX utility, performing a line-by-line rot-13 encoding of every line of input contained in each file listed on its command line, or (if no filenames are passed thereon) acting as a filter on its "standard input." (A number of UNIX scripting languages and utilities, such as awk and sed either default to processing files in this way or have command line switches or modules to easily implement these wrapper semantics, e.g., Perl and Python). The rot-13 encoding is commonly known from the early days of Usenet "Netnews" as a way of obfuscating text to prevent casual reading of spoiler or potentially offensive material. Many news reader and mail user agent programs have built-in rot-13 encoder/decoders or have the ability to feed a message through any external utility script for performing this (or other) actions. The definition of the rot-13 function is to simply replace every letter of the ASCII alphabet with the letter which is "rotated" 13 characters "around" the 26 letter alphabet from its normal cardinal position (wrapping around from z to a as necessary). Thus the letters abc become nop and so on. Technically rot-13 is a "mono-alphabetic substitution cipher" with a trivial "key". A proper implementation should work on upper and lower case letters, preserve case, and pass all non-alphabetic characters in the input stream through without alteration. Related tasks Caesar cipher Substitution Cipher Vigenère Cipher/Cryptanalysis Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet

#SNOBOL4

SNOBOL4

* # Function using replace( ) define('rot13(s)u1,u2,l1,l2') :(rot13_end) rot13 &ucase len(13) . u1 rem . u2 &lcase len(13) . l1 rem . l2 rot13 = replace(s,&ucase &lcase,u2 u1 l2 l1) :(return) rot13_end * # Function using pattern define('rot13s(s)c') alfa = &ucase &ucase &lcase &lcase :(rot13s_end) rot13s s len(1) . c = :f(return) alfa break(c) len(13) len(1) . c rot13s = rot13s c :(rot13s) rot13s_end * # Test and display both str = rot13("I abjure the $19.99 trinket!") output = str; output = rot13(str) str = rot13s("He's a real Nowhere Man.") output = str; output = rot13s(str) end

http://rosettacode.org/wiki/Roman_numerals/Encode

Roman numerals/Encode

Task Create a function taking a positive integer as its parameter and returning a string containing the Roman numeral representation of that integer. Modern Roman numerals are written by expressing each digit separately, starting with the left most digit and skipping any digit with a value of zero. In Roman numerals: 1990 is rendered: 1000=M, 900=CM, 90=XC; resulting in MCMXC 2008 is written as 2000=MM, 8=VIII; or MMVIII 1666 uses each Roman symbol in descending order: MDCLXVI

#Sidef

Sidef

func arabic2roman(num, roman='') { static lookup = [ :M:1000, :CM:900, :D:500, :CD:400, :C:100, :XC:90, :L:50, :XL:40, :X:10, :IX:9, :V:5, :IV:4, :I:1 ]; lookup.each { |pair| while (num >= pair.second) { roman += pair.first; num -= pair.second; } } return roman; } say("1990 in roman is " + arabic2roman(1990)); say("2008 in roman is " + arabic2roman(2008)); say("1666 in roman is " + arabic2roman(1666));

http://rosettacode.org/wiki/Roman_numerals/Decode

Roman numerals/Decode

Task Create a function that takes a Roman numeral as its argument and returns its value as a numeric decimal integer. You don't need to validate the form of the Roman numeral. Modern Roman numerals are written by expressing each decimal digit of the number to be encoded separately, starting with the leftmost decimal digit and skipping any 0s (zeroes). 1990 is rendered as MCMXC (1000 = M, 900 = CM, 90 = XC) and 2008 is rendered as MMVIII (2000 = MM, 8 = VIII). The Roman numeral for 1666, MDCLXVI, uses each letter in descending order.

#zkl

zkl

http://rosettacode.org/wiki/Repeat_a_string

Repeat a string

Take a string and repeat it some number of times. Example: repeat("ha", 5) => "hahahahaha" If there is a simpler/more efficient way to repeat a single “character” (i.e. creating a string filled with a certain character), you might want to show that as well (i.e. repeat-char("*", 5) => "*****"). Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet

#GAP

GAP

Concatenation(ListWithIdenticalEntries(10, "BOB ")); "BOB BOB BOB BOB BOB BOB BOB BOB BOB BOB "

http://rosettacode.org/wiki/Repeat_a_string

Repeat a string

Take a string and repeat it some number of times. Example: repeat("ha", 5) => "hahahahaha" If there is a simpler/more efficient way to repeat a single “character” (i.e. creating a string filled with a certain character), you might want to show that as well (i.e. repeat-char("*", 5) => "*****"). Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet

#Glee

Glee

'*' %% 5

http://rosettacode.org/wiki/Return_multiple_values

Return multiple values

Task Show how to return more than one value from a function.

#PowerShell

PowerShell

function multiple-value ($a, $b) { [pscustomobject]@{ a = $a b = $b } } $m = multiple-value "value" 1 $m.a $m.b

http://rosettacode.org/wiki/Return_multiple_values

Return multiple values

Task Show how to return more than one value from a function.

#PureBasic

PureBasic

;An array, map, or list can be used as a parameter to a procedure and in the ;process contain values to be returned as well. Procedure example_1(x, y, Array r(1)) ;array r() will contain the return values Dim r(2) ;clear and resize the array r(0) = x + y ;return these values in the array r(1) = x - y r(2) = x * y EndProcedure ;A pointer to memory or a structured variable may also be returned to reference ;multiple return values (requiring the memory to be manually freed afterwards). Procedure example_2(x, y) Protected *result.POINT = AllocateMemory(SizeOf(POINT)) *result\x = x *result\y = y ProcedureReturn *result ;*result points to a 'POINT' structure containing x and y EndProcedure If OpenConsole() Dim a(5) example_1(6, 5, a()) ;a() now contains {11, 1, 30} PrintN("Array returned with {" + Str(a(0)) + ", " + Str(a(1)) + ", " + Str(a(2)) + "}") Define *aPoint.POINT *aPoint = example_2(6, 5) ;*aPoint references structured memory containing {6, 5} PrintN("structured memory holds: (" + Str(*aPoint\x) + ", " + Str(*aPoint\y) + ")") FreeMemory(*aPoint) ;freememory Print(#CRLF$ + #CRLF$ + "Press ENTER to exit"): Input() CloseConsole() EndIf

http://rosettacode.org/wiki/Remove_duplicate_elements

Remove duplicate elements

Sorting Algorithm This is a sorting algorithm. It may be applied to a set of data in order to sort it. For comparing various sorts, see compare sorts. For other sorting algorithms, see sorting algorithms, or: O(n logn) sorts Heap sort | Merge sort | Patience sort | Quick sort O(n log2n) sorts Shell Sort O(n2) sorts Bubble sort | Cocktail sort | Cocktail sort with shifting bounds | Comb sort | Cycle sort | Gnome sort | Insertion sort | Selection sort | Strand sort other sorts Bead sort | Bogo sort | Common sorted list | Composite structures sort | Custom comparator sort | Counting sort | Disjoint sublist sort | External sort | Jort sort | Lexicographical sort | Natural sorting | Order by pair comparisons | Order disjoint list items | Order two numerical lists | Object identifier (OID) sort | Pancake sort | Quickselect | Permutation sort | Radix sort | Ranking methods | Remove duplicate elements | Sleep sort | Stooge sort | [Sort letters of a string] | Three variable sort | Topological sort | Tree sort Given an Array, derive a sequence of elements in which all duplicates are removed. There are basically three approaches seen here: Put the elements into a hash table which does not allow duplicates. The complexity is O(n) on average, and O(n2) worst case. This approach requires a hash function for your type (which is compatible with equality), either built-in to your language, or provided by the user. Sort the elements and remove consecutive duplicate elements. The complexity of the best sorting algorithms is O(n log n). This approach requires that your type be "comparable", i.e., have an ordering. Putting the elements into a self-balancing binary search tree is a special case of sorting. Go through the list, and for each element, check the rest of the list to see if it appears again, and discard it if it does. The complexity is O(n2). The up-shot is that this always works on any type (provided that you can test for equality).

#F.23

F#

set [|1;2;3;2;3;4|]

http://rosettacode.org/wiki/Recaman%27s_sequence

Recaman's sequence

The Recamán's sequence generates Natural numbers. Starting from a(0)=0, the n'th term a(n), where n>0, is the previous term minus n i.e a(n) = a(n-1) - n but only if this is both positive and has not been previousely generated. If the conditions don't hold then a(n) = a(n-1) + n. Task Generate and show here the first 15 members of the sequence. Find and show here, the first duplicated number in the sequence. Optionally: Find and show here, how many terms of the sequence are needed until all the integers 0..1000, inclusive, are generated. References A005132, The On-Line Encyclopedia of Integer Sequences. The Slightly Spooky Recamán Sequence, Numberphile video. Recamán's sequence, on Wikipedia.

#PL.2FM

PL/M

100H: BDOS: PROCEDURE(F,A); DECLARE F BYTE, A ADDRESS; GO TO 5; END BDOS; EXIT: PROCEDURE; CALL BDOS(0,0); END EXIT; PRINT$CH: PROCEDURE(C); DECLARE C BYTE; CALL BDOS(2,C); END PRINT$CH; PRINT$STR: PROCEDURE(S); DECLARE S ADDRESS; CALL BDOS(9,S); END PRINT$STR; /* PRINT NUMBER */ PRINT$NUM: PROCEDURE(N); DECLARE (N, P) ADDRESS, C BASED P BYTE; DECLARE S(6) BYTE INITIAL('.....$'); P = .S(5); DIGIT: P = P-1; C = '0' + N MOD 10; N = N/10; IF N>0 THEN GO TO DIGIT; CALL PRINT$STR(P); END PRINT$NUM; /* IS X IN THE FIRST N TERMS OF THE SEQUENCE */ FIND: PROCEDURE(SEQ,X,N) BYTE; DECLARE SEQ ADDRESS, (I, X, N, A BASED SEQ) BYTE; DO I=0 TO N-1; IF A(I)=X THEN RETURN 0FFH; END; RETURN 0; END FIND; /* GENERATE THE N'TH TERM OF THE SEQUENCE */ GENERATE: PROCEDURE(SEQ,N) BYTE; DECLARE SEQ ADDRESS, (N, A BASED SEQ) BYTE; IF N=0 THEN A(N)=0; ELSE DO; DECLARE (SUB, ADD) BYTE; SUB = A(N-1) - N; ADD = A(N-1) + N; /* A(N-1) - N NEGATIVE? */ IF A(N-1) <= N THEN A(N) = ADD; /* A(N-1) - N ALREADY GENERATED? */ ELSE IF FIND(SEQ,SUB,N) THEN A(N) = ADD; ELSE A(N) = SUB; END; RETURN A(N); END GENERATE; DECLARE I BYTE, A(30) BYTE; CALL PRINT$STR(.'FIRST 15 MEMBERS: $'); DO I=0 TO 14; CALL PRINT$NUM(GENERATE(.A, I)); CALL PRINT$CH(' '); END; CALL PRINT$STR(.(13,10,'FIRST REPEATED TERM: A($')); I=15; DO WHILE NOT FIND(.A, GENERATE(.A, I), I); I = I+1; END; CALL PRINT$NUM(I); CALL PRINT$STR(.') = $'); CALL PRINT$NUM(A(I)); CALL PRINT$STR(.(13,10,'$')); CALL EXIT; EOF

http://rosettacode.org/wiki/Reduced_row_echelon_form

Reduced row echelon form

Reduced row echelon form You are encouraged to solve this task according to the task description, using any language you may know. Task Show how to compute the reduced row echelon form (a.k.a. row canonical form) of a matrix. The matrix can be stored in any datatype that is convenient (for most languages, this will probably be a two-dimensional array). Built-in functions or this pseudocode (from Wikipedia) may be used: function ToReducedRowEchelonForm(Matrix M) is lead := 0 rowCount := the number of rows in M columnCount := the number of columns in M for 0 ≤ r < rowCount do if columnCount ≤ lead then stop end if i = r while M[i, lead] = 0 do i = i + 1 if rowCount = i then i = r lead = lead + 1 if columnCount = lead then stop end if end if end while Swap rows i and r If M[r, lead] is not 0 divide row r by M[r, lead] for 0 ≤ i < rowCount do if i ≠ r do Subtract M[i, lead] multiplied by row r from row i end if end for lead = lead + 1 end for end function For testing purposes, the RREF of this matrix: 1 2 -1 -4 2 3 -1 -11 -2 0 -3 22 is: 1 0 0 -8 0 1 0 1 0 0 1 -2

#Java

Java

import java.util.*; import java.lang.Math; import org.apache.commons.math.fraction.Fraction; import org.apache.commons.math.fraction.FractionConversionException; /* Matrix class * Handles elementary Matrix operations: * Interchange * Multiply and Add * Scale * Reduced Row Echelon Form */ class Matrix { LinkedList<LinkedList<Fraction>> matrix; int numRows; int numCols; static class Coordinate { int row; int col; Coordinate(int r, int c) { row = r; col = c; } public String toString() { return "(" + row + ", " + col + ")"; } } Matrix(double [][] m) { numRows = m.length; numCols = m[0].length; matrix = new LinkedList<LinkedList<Fraction>>(); for (int i = 0; i < numRows; i++) { matrix.add(new LinkedList<Fraction>()); for (int j = 0; j < numCols; j++) { try { matrix.get(i).add(new Fraction(m[i][j])); } catch (FractionConversionException e) { System.err.println("Fraction could not be converted from double by apache commons . . ."); } } } } public void Interchange(Coordinate a, Coordinate b) { LinkedList<Fraction> temp = matrix.get(a.row); matrix.set(a.row, matrix.get(b.row)); matrix.set(b.row, temp); int t = a.row; a.row = b.row; b.row = t; } public void Scale(Coordinate x, Fraction d) { LinkedList<Fraction> row = matrix.get(x.row); for (int i = 0; i < numCols; i++) { row.set(i, row.get(i).multiply(d)); } } public void MultiplyAndAdd(Coordinate to, Coordinate from, Fraction scalar) { LinkedList<Fraction> row = matrix.get(to.row); LinkedList<Fraction> rowMultiplied = matrix.get(from.row); for (int i = 0; i < numCols; i++) { row.set(i, row.get(i).add((rowMultiplied.get(i).multiply(scalar)))); } } public void RREF() { Coordinate pivot = new Coordinate(0,0); int submatrix = 0; for (int x = 0; x < numCols; x++) { pivot = new Coordinate(pivot.row, x); //Step 1 //Begin with the leftmost nonzero column. This is a pivot column. The pivot position is at the top. for (int i = x; i < numCols; i++) { if (isColumnZeroes(pivot) == false) { break; } else { pivot.col = i; } } //Step 2 //Select a nonzero entry in the pivot column with the highest absolute value as a pivot. pivot = findPivot(pivot); if (getCoordinate(pivot).doubleValue() == 0.0) { pivot.row++; continue; } //If necessary, interchange rows to move this entry into the pivot position. //move this row to the top of the submatrix if (pivot.row != submatrix) { Interchange(new Coordinate(submatrix, pivot.col), pivot); } //Force pivot to be 1 if (getCoordinate(pivot).doubleValue() != 1) { /* System.out.println(getCoordinate(pivot)); System.out.println(pivot); System.out.println(matrix); */ Fraction scalar = getCoordinate(pivot).reciprocal(); Scale(pivot, scalar); } //Step 3 //Use row replacement operations to create zeroes in all positions below the pivot. //belowPivot = belowPivot + (Pivot * -belowPivot) for (int i = pivot.row; i < numRows; i++) { if (i == pivot.row) { continue; } Coordinate belowPivot = new Coordinate(i, pivot.col); Fraction complement = (getCoordinate(belowPivot).negate().divide(getCoordinate(pivot))); MultiplyAndAdd(belowPivot, pivot, complement); } //Step 5 //Beginning with the rightmost pivot and working upward and to the left, create zeroes above each pivot. //If a pivot is not 1, make it 1 by a scaling operation. //Use row replacement operations to create zeroes in all positions above the pivot for (int i = pivot.row; i >= 0; i--) { if (i == pivot.row) { if (getCoordinate(pivot).doubleValue() != 1.0) { Scale(pivot, getCoordinate(pivot).reciprocal()); } continue; } if (i == pivot.row) { continue; } Coordinate abovePivot = new Coordinate(i, pivot.col); Fraction complement = (getCoordinate(abovePivot).negate().divide(getCoordinate(pivot))); MultiplyAndAdd(abovePivot, pivot, complement); } //Step 4 //Ignore the row containing the pivot position and cover all rows, if any, above it. //Apply steps 1-3 to the remaining submatrix. Repeat until there are no more nonzero entries. if ((pivot.row + 1) >= numRows || isRowZeroes(new Coordinate(pivot.row+1, pivot.col))) { break; } submatrix++; pivot.row++; } } public boolean isColumnZeroes(Coordinate a) { for (int i = 0; i < numRows; i++) { if (matrix.get(i).get(a.col).doubleValue() != 0.0) { return false; } } return true; } public boolean isRowZeroes(Coordinate a) { for (int i = 0; i < numCols; i++) { if (matrix.get(a.row).get(i).doubleValue() != 0.0) { return false; } } return true; } public Coordinate findPivot(Coordinate a) { int first_row = a.row; Coordinate pivot = new Coordinate(a.row, a.col); Coordinate current = new Coordinate(a.row, a.col); for (int i = a.row; i < (numRows - first_row); i++) { current.row = i; if (getCoordinate(current).doubleValue() == 1.0) { Interchange(current, a); } } current.row = a.row; for (int i = current.row; i < (numRows - first_row); i++) { current.row = i; if (getCoordinate(current).doubleValue() != 0) { pivot.row = i; break; } } return pivot; } public Fraction getCoordinate(Coordinate a) { return matrix.get(a.row).get(a.col); } public String toString() { return matrix.toString().replace("], ", "]\n"); } public static void main (String[] args) { double[][] matrix_1 = { {1, 2, -1, -4}, {2, 3, -1, -11}, {-2, 0, -3, 22} }; Matrix x = new Matrix(matrix_1); System.out.println("before\n" + x.toString() + "\n"); x.RREF(); System.out.println("after\n" + x.toString() + "\n"); double matrix_2 [][] = { {2, 0, -1, 0, 0}, {1, 0, 0, -1, 0}, {3, 0, 0, -2, -1}, {0, 1, 0, 0, -2}, {0, 1, -1, 0, 0} }; Matrix y = new Matrix(matrix_2); System.out.println("before\n" + y.toString() + "\n"); y.RREF(); System.out.println("after\n" + y.toString() + "\n"); double matrix_3 [][] = { {1, 2, 3, 4, 3, 1}, {2, 4, 6, 2, 6, 2}, {3, 6, 18, 9, 9, -6}, {4, 8, 12, 10, 12, 4}, {5, 10, 24, 11, 15, -4} }; Matrix z = new Matrix(matrix_3); System.out.println("before\n" + z.toString() + "\n"); z.RREF(); System.out.println("after\n" + z.toString() + "\n"); double matrix_4 [][] = { {0, 1}, {1, 2}, {0,5} }; Matrix a = new Matrix(matrix_4); System.out.println("before\n" + a.toString() + "\n"); a.RREF(); System.out.println("after\n" + a.toString() + "\n"); } }

http://rosettacode.org/wiki/Real_constants_and_functions

Real constants and functions

Task Show how to use the following math constants and functions in your language (if not available, note it): e (base of the natural logarithm) π {\displaystyle \pi } square root logarithm (any base allowed) exponential (ex ) absolute value (a.k.a. "magnitude") floor (largest integer less than or equal to this number--not the same as truncate or int) ceiling (smallest integer not less than this number--not the same as round up) power (xy ) Related task Trigonometric Functions

#Forth

Forth

1e fexp fconstant e 0e facos 2e f* fconstant pi \ predefined in gforth fsqrt ( f -- f ) fln ( f -- f ) \ flog for base 10 fexp ( f -- f ) fabs ( f -- f ) floor ( f -- f ) \ round towards -inf : ceil ( f -- f ) fnegate floor fnegate ; \ not standard, though fround is available f** ( f e -- f^e )

http://rosettacode.org/wiki/Real_constants_and_functions

Real constants and functions

Task Show how to use the following math constants and functions in your language (if not available, note it): e (base of the natural logarithm) π {\displaystyle \pi } square root logarithm (any base allowed) exponential (ex ) absolute value (a.k.a. "magnitude") floor (largest integer less than or equal to this number--not the same as truncate or int) ceiling (smallest integer not less than this number--not the same as round up) power (xy ) Related task Trigonometric Functions

#Fortran

Fortran

e ! Not available. Can be calculated EXP(1.0) pi ! Not available. Can be calculated 4.0*ATAN(1.0) SQRT(x) ! square root LOG(x) ! natural logarithm LOG10(x) ! logarithm to base 10 EXP(x) ! exponential ABS(x) ! absolute value FLOOR(x) ! floor - Fortran 90 or later only CEILING(x) ! ceiling - Fortran 90 or later only x**y ! x raised to the y power

http://rosettacode.org/wiki/Remove_lines_from_a_file

Remove lines from a file

Task Remove a specific line or a number of lines from a file. This should be implemented as a routine that takes three parameters (filename, starting line, and the number of lines to be removed). For the purpose of this task, line numbers and the number of lines start at one, so to remove the first two lines from the file foobar.txt, the parameters should be: foobar.txt, 1, 2 Empty lines are considered and should still be counted, and if the specified line is empty, it should still be removed. An appropriate message should appear if an attempt is made to remove lines beyond the end of the file.

#Oforth

Oforth

: removeLines(filename, startLine, numLines) | line b endLine | ListBuffer new ->b startLine numLines + 1 - ->endLine 0 File new(filename) forEach: line [ 1+ dup between(startLine, endLine) ifFalse: [ b add(line) continue ] numLines 1- ->numLines ] drop numLines 0 == ifFalse: [ "Error : Removing lines beyond end of file" println return ] File new(filename) dup open(File.WRITE) b apply(#[ << dup cr ]) close ;

http://rosettacode.org/wiki/Remove_lines_from_a_file

Remove lines from a file

Task Remove a specific line or a number of lines from a file. This should be implemented as a routine that takes three parameters (filename, starting line, and the number of lines to be removed). For the purpose of this task, line numbers and the number of lines start at one, so to remove the first two lines from the file foobar.txt, the parameters should be: foobar.txt, 1, 2 Empty lines are considered and should still be counted, and if the specified line is empty, it should still be removed. An appropriate message should appear if an attempt is made to remove lines beyond the end of the file.

#Pascal

Pascal

program RemLines; {$mode objfpc}{$H+} uses {$IFDEF UNIX}{$IFDEF UseCThreads} cthreads, {$ENDIF}{$ENDIF} Classes, SysUtils; type TRLResponse=(rlrOk, rlrEmptyFile, rlrNotEnoughLines); function RemoveLines(const FileName: String; const From, Count: Integer): TRLResponse; const LineOffs = Length(LineEnding); var TIn, TOut: TFileStream; tmpFn, MemBuff, FileBuff: String; EndingPos, CharRead, LineNumber: Integer; procedure WriteLine(Line: String); begin if ((From > 1) and (LineNumber = 1)) or ((From = 1) and (LineNumber = (From+Count))) then // First line to write, without LineEnding => Line unchanged else if ((From = 1) or (From <= LineNumber)) and (LineNumber < (From+Count)) then // No line to write Line := '' else // all other cases, write Line preceded (!) by LineEnding Line := LineEnding + Line; // Write if Line <> '' then TOut.Write(Line[1], Length(Line)); End; begin if not FileExists(FileName) then raise Exception.CreateFmt('No such file %s', [FileName]); if From < 1 then raise Exception.Create('First line must be >= 1'); tmpFn := GetTempFileName(ExtractFilePath(FileName), ''); TIn := TFileStream.Create(FileName, fmOpenRead); try TOut := TFileStream.Create(tmpFn, fmCreate); try FileBuff := StringOfChar(' ', 1024); // Reserve memory in a string LineNumber := 0; MemBuff := ''; while True do begin CharRead := TIn.Read(FileBuff[1], 1024); if (CharRead = 0) then break; // no more char to process MemBuff += Copy(FileBuff, 1, CharRead); // op += is FPC specific while True do begin // LineEnding can contain 1 or 2 chars, depending on the OS EndingPos := Pos(LineEnding, MemBuff); if EndingPos = 0 then break; // EndingLine in the next reading, maybe Inc(LineNumber); WriteLine(Copy(MemBuff, 1, EndingPos - 1)); MemBuff := Copy(MemBuff, EndingPos + LineOffs, MaxInt); // Loop for another line in MemBuff end; end; Inc(LineNumber); WriteLine(MemBuff); // Writes what remains finally TOut.Free; end; finally TIn.Free; end; // Temp File replaces the original file. if DeleteFile(FileName) then RenameFile(tmpFn, FileName) else raise Exception.Create('Unable to process the file'); // Response if (LineNumber = 0) then Result := rlrEmptyFile else if (LineNumber < (From+Count-1)) then Result := rlrNotEnoughLines else Result := rlrOk; End; var FileName: String; begin FileName := IncludeTrailingPathDelimiter(ExtractFilePath(ParamStr(0))) + 'test.txt'; try case RemoveLines(FileName, 4, 3) of rlrOk: WriteLn('Lines deleted'); rlrEmptyFile: WriteLn(Format('File "%s" is empty!', [FileName])); rlrNotEnoughLines: WriteLn('Can''t delete lines past the end of file'); end except on E: Exception do WriteLn('Error: ' + E.Message); end; ReadLn; End.

http://rosettacode.org/wiki/Read_entire_file

Read entire file

Task Load the entire contents of some text file as a single string variable. If applicable, discuss: encoding selection, the possibility of memory-mapping. Of course, in practice one should avoid reading an entire file at once if the file is large and the task can be accomplished incrementally instead (in which case check File IO); this is for those cases where having the entire file is actually what is wanted.

#GUISS

GUISS

Start,Programs,Accessories,Notepad,Menu:File,Open,Doubleclick:Icon:Notes.TXT,Button:OK

http://rosettacode.org/wiki/Read_entire_file

Read entire file

Task Load the entire contents of some text file as a single string variable. If applicable, discuss: encoding selection, the possibility of memory-mapping. Of course, in practice one should avoid reading an entire file at once if the file is large and the task can be accomplished incrementally instead (in which case check File IO); this is for those cases where having the entire file is actually what is wanted.

#Haskell

Haskell

do text <- readFile filepath -- do stuff with text

http://rosettacode.org/wiki/Rep-string

Rep-string

Given a series of ones and zeroes in a string, define a repeated string or rep-string as a string which is created by repeating a substring of the first N characters of the string truncated on the right to the length of the input string, and in which the substring appears repeated at least twice in the original. For example, the string 10011001100 is a rep-string as the leftmost four characters of 1001 are repeated three times and truncated on the right to give the original string. Note that the requirement for having the repeat occur two or more times means that the repeating unit is never longer than half the length of the input string. Task Write a function/subroutine/method/... that takes a string and returns an indication of if it is a rep-string and the repeated string. (Either the string that is repeated, or the number of repeated characters would suffice). There may be multiple sub-strings that make a string a rep-string - in that case an indication of all, or the longest, or the shortest would suffice. Use the function to indicate the repeating substring if any, in the following: 1001110011 1110111011 0010010010 1010101010 1111111111 0100101101 0100100 101 11 00 1 Show your output on this page. Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet

#PL.2FM

PL/M

100H: DECLARE MAX$REP LITERALLY '32'; DECLARE FALSE LITERALLY '0'; DECLARE TRUE LITERALLY '1'; DECLARE CR LITERALLY '0DH'; DECLARE LF LITERALLY '0AH'; /* CP/M BDOS SYSTEM CALL */ BDOS: PROCEDURE( FN, ARG ); DECLARE FN BYTE, ARG ADDRESS; GOTO 5; END; /* PRINTS A BYTE AS A CHARACTER */ PRINT$CHAR: PROCEDURE( CH ); DECLARE CH BYTE; CALL BDOS( 2, CH ); END; /* PRINTS A $ TERMINATED STRING */ PRINT$STRING: PROCEDURE( S ); DECLARE S ADDRESS; CALL BDOS( 9, S ); END; /* PRINTS A BYTE AS A NUMBER */ PRINT$BYTE: PROCEDURE( N ); DECLARE N BYTE; DECLARE ( V, D2, D3 ) BYTE; V = N; D3 = V MOD 10; IF ( V := V / 10 ) <> 0 THEN DO; D2 = V MOD 10; IF ( V := V / 10 ) <> 0 THEN CALL PRINT$CHAR( '0' + V ); CALL PRINT$CHAR( '0' + D2 ); END; CALL PRINT$CHAR( '0' + D3 ); END PRINT$BYTE; /* PRINTS A FIXED LENGTH STRING */ PRINT$SUBSTRING: PROCEDURE( S$PTR, LEN ); DECLARE S$PTR ADDRESS, LEN BYTE, S BASED S$PTR ( MAX$REP )BYTE; DECLARE S$POS BYTE; DO S$POS = 0 TO LEN - 1; CALL PRINT$CHAR( S( S$POS ) ); END; END PRINT$SUBSTRING; /* RETURNS THE LENGTH OF A $ TERMINATED STRING */ STR$LENGTH: PROCEDURE( S$PTR )BYTE; DECLARE S$PTR ADDRESS, S BASED S$PTR ( MAX$REP )BYTE; DECLARE RESULT BYTE; RESULT = 0; DO WHILE( S( RESULT ) <> '$' ); RESULT = RESULT + 1; END; RETURN RESULT; END STR$LENGTH; /* RETURNS THE LENGTH OF THE LONGEST REP-STRING IN S$PTR, */ LONGEST$REP$STRING: PROCEDURE( S$PTR )BYTE; DECLARE S$PTR ADDRESS, S BASED S$PTR ( MAX$REP )BYTE; DECLARE ( S$LEN, RESULT, S$POS, R$POS, I, FOUND ) BYTE; RESULT = 0; FOUND = FALSE; S$LEN = STR$LENGTH( S$PTR ); S$POS = ( S$LEN / 2 ) - 1; /* IF ( S$LEN / 2 ) = 0, S$POS WILL BE 255 */ DO WHILE( NOT FOUND AND S$POS < 255 ); /* AS BYTE/ADDRESS ARE UNSIGNED */ /* CHECK THE POTENTIAL REP-STRING REPEATED A SUFFICIENT NUMBER */ /* OF TIMES (TRUNCATED IF NECESSARY) EQUALS THE ORIGINAL STRING */ FOUND = TRUE; R$POS = S$POS + 1; DO WHILE( FOUND AND R$POS < S$LEN AND FOUND ); I = 0; DO WHILE( I <= S$POS AND R$POS < S$LEN AND FOUND ); FOUND = S( R$POS ) = S( I ); R$POS = R$POS + 1; I = I + 1; END; END; IF NOT FOUND THEN DO; /* HAVEN'T FOUND A REP-STRING, TRY A SHORTER ONE */ S$POS = S$POS - 1; /* S$POS WILL BECOME 255 IF S$POS = 0 */ END; END; IF FOUND THEN DO; RESULT = S$POS + 1; END; RETURN RESULT; END LONGEST$REP$STRING; DECLARE ( TEST$NUMBER, REP$STRING$LEN ) BYTE; DECLARE TESTS ( 11 )ADDRESS; TESTS( 0 ) = .'1001110011$'; TESTS( 1 ) = .'1110111011$'; TESTS( 2 ) = .'0010010010$'; TESTS( 3 ) = .'1010101010$'; TESTS( 4 ) = .'1111111111$'; TESTS( 5 ) = .'0100101101$'; TESTS( 6 ) = .'0100100$'; TESTS( 7 ) = .'101$'; TESTS( 8 ) = .'11$'; TESTS( 9 ) = .'00$'; TESTS( 10 ) = .'1$'; DO TEST$NUMBER = 0 TO LAST( TESTS ); REP$STRING$LEN = LONGEST$REP$STRING( TESTS( TEST$NUMBER ) ); CALL PRINT$STRING( TESTS( TEST$NUMBER ) ); IF REP$STRING$LEN = 0 THEN DO; CALL PRINT$STRING( .': NO REP STRING$' ); END; ELSE DO; CALL PRINT$STRING( .': LONGEST REP STRING: $' ); CALL PRINT$SUBSTRING( TESTS( TEST$NUMBER ), REP$STRING$LEN ); END; CALL PRINT$STRING( .( CR, LF, '$' ) ); END; EOF

http://rosettacode.org/wiki/Rep-string

Rep-string

Given a series of ones and zeroes in a string, define a repeated string or rep-string as a string which is created by repeating a substring of the first N characters of the string truncated on the right to the length of the input string, and in which the substring appears repeated at least twice in the original. For example, the string 10011001100 is a rep-string as the leftmost four characters of 1001 are repeated three times and truncated on the right to give the original string. Note that the requirement for having the repeat occur two or more times means that the repeating unit is never longer than half the length of the input string. Task Write a function/subroutine/method/... that takes a string and returns an indication of if it is a rep-string and the repeated string. (Either the string that is repeated, or the number of repeated characters would suffice). There may be multiple sub-strings that make a string a rep-string - in that case an indication of all, or the longest, or the shortest would suffice. Use the function to indicate the repeating substring if any, in the following: 1001110011 1110111011 0010010010 1010101010 1111111111 0100101101 0100100 101 11 00 1 Show your output on this page. Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet

#Prolog

Prolog

:- use_module(library(func)). %% Implementation logic: test_for_repstring(String, (String, Result, Reps)) :- ( setof(Rep, repstring(String, Rep), Reps) -> Result = 'no repstring' ; Result = 'repstrings', Reps = [] ). repstring(Codes, R) :- RepLength = between(1) of (_//2) of length $ Codes, length(R, RepLength), phrase( (rep(R), prefix(~,R)), Codes). rep(X) --> X, X. rep(X) --> X, rep(X). %% Demonstration output: test_strings([`1001110011`, `1110111011`, `0010010010`, `1010101010`, `1111111111`, `0100101101`, `0100100`, `101`, `11`, `00`, `1`]). report_repstring((S,Result,Reps)):- format('~s -- ~w: ', [S, Result]), foreach(member(R, Reps), format('~s, ', [R])), nl. report_repstrings :- Results = maplist(test_for_repstring) $ test_strings(~), maplist(report_repstring, Results).

http://rosettacode.org/wiki/Regular_expressions

Regular expressions

Task match a string against a regular expression substitute part of a string using a regular expression

#Oz

Oz

declare [Regex] = {Module.link ['x-oz://contrib/regex']} String = "This is a string" in if {Regex.search "string$" String} \= false then {System.showInfo "Ends with string."} end {System.showInfo {Regex.replace String " a " fun {$ _ _} " another " end}}

http://rosettacode.org/wiki/Regular_expressions

Regular expressions

Task match a string against a regular expression substitute part of a string using a regular expression

#Pascal

Pascal

// Match and Replace part of a string using a Regular Expression // // Nigel Galloway - April 11th., 2012 // program RegularExpr; uses RegExpr; const myString = 'I think that I am Nigel'; myMatch = '(I am)|(you are)'; var r : TRegExpr; myResult : String; begin r := TRegExpr.Create; r.Expression := myMatch; write(myString); if r.Exec(myString) then writeln(' contains ' + r.Match[0]); myResult := r.Replace(myString, 'you are', False); write(myResult); if r.Exec(myResult) then writeln(' contains ' + r.Match[0]); end.

http://rosettacode.org/wiki/Reverse_a_string

Reverse a string

Task Take a string and reverse it. For example, "asdf" becomes "fdsa". Extra credit Preserve Unicode combining characters. For example, "as⃝df̅" becomes "f̅ds⃝a", not "̅fd⃝sa". Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet

#ColdFusion

ColdFusion

http://rosettacode.org/wiki/Repeat

Repeat

Task Write a procedure which accepts as arguments another procedure and a positive integer. The latter procedure is executed a number of times equal to the accepted integer.

#Verilog

Verilog

module main; initial begin repeat(5) begin $display("Inside loop"); end $display("Loop Ended"); end endmodule

http://rosettacode.org/wiki/Repeat

Repeat

Task Write a procedure which accepts as arguments another procedure and a positive integer. The latter procedure is executed a number of times equal to the accepted integer.

#Visual_Basic_.NET

Visual Basic .NET

Module Module1 Sub Repeat(count As Integer, fn As Action(Of Integer)) If IsNothing(fn) Then Throw New ArgumentNullException("fn") End If For i = 1 To count fn.Invoke(i) Next End Sub Sub Main() Repeat(3, Sub(x) Console.WriteLine("Example {0}", x)) End Sub End Module

http://rosettacode.org/wiki/Rename_a_file

Rename a file

Task Rename: a file called input.txt into output.txt and a directory called docs into mydocs. This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root. It can be assumed that the user has the rights to do so. (In unix-type systems, only the user root would have sufficient permissions in the filesystem root.)

#PureBasic

PureBasic

RenameFile("input.txt", "output.txt") RenameFile("docs\", "mydocs\") RenameFile("/input.txt","/output.txt") RenameFile("/docs\","/mydocs\")