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http://rosettacode.org/wiki/Resistor_mesh
Resistor mesh
Task Given   10×10   grid nodes   (as shown in the image)   interconnected by   1Ω   resistors as shown, find the resistance between points   A   and   B. See also   (humor, nerd sniping)   xkcd.com cartoon
#Raku
Raku
my $*TOLERANCE = 1e-12;   sub set-boundary(@mesh,@p1,@p2) { @mesh[ @p1[0] ; @p1[1] ] = 1; @mesh[ @p2[0] ; @p2[1] ] = -1; }   sub solve(@p1, @p2, Int \w, Int \h) { my @d = [0 xx w] xx h; my @V = [0 xx w] xx h; my @fixed = [0 xx w] xx h; set-boundary(@fixed,@p1,@p2);   loop { set-boundary(@V,@p1,@p2); my $diff = 0; for (flat ^h X ^w) -> \i, \j { my @neighbors = (@V[i-1;j], @V[i;j-1], @V[i+1;j], @V[i;j+1]).grep: *.defined; @d[i;j] = my \v = @V[i;j] - @neighbors.sum / @neighbors; $diff += v × v unless @fixed[i;j]; } last if $diff =~= 0;   for (flat ^h X ^w) -> \i, \j { @V[i;j] -= @d[i;j]; } }   my @current; for (flat ^h X ^w) -> \i, \j { @current[ @fixed[i;j]+1 ] += @d[i;j] × (?i + ?j + (i < h-1) + (j < w-1) ); } (@current[2] - @current[0]) / 2 }   say 2 / solve (1,1), (6,7), 10, 10;  
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
#Elm
Elm
  reversedPoem = String.trim """ ---------- 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 ----------------------- """   reverseWords string = string |> String.words |> List.reverse |> String.join " "   reverseLinesWords string = string |> String.lines |> List.map reverseWords |> String.join "\n"   poem = reverseLinesWords reversedPoem  
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
#Emacs_Lisp
Emacs Lisp
(defun reverse-words (line) (insert (format "%s\n" (mapconcat 'identity (reverse (split-string line)) " "))))   (defun reverse-lines (lines) (mapcar 'reverse-words lines))   (reverse-lines '("---------- 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/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
#Pop11
Pop11
define rot13(s); lvars j, c; for j from 1 to length(s) do s(j) -> c; if `A` <= c and c <= `M` or `a` <= c and c <= `m` then c + 13 -> s(j); elseif `N` <= c and c <= `Z` or `n` <= c and c <= `z` then c - 13 -> s(j); endif; endfor; s; enddefine;   rot13('NOPQRSTUVWXYZABCDEFGHIJKLMnopqrstuvwxyzabcdefghijklm') =>
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
#Phixmonti
Phixmonti
include ..\Utilitys.pmt   def romanEnc /# n -- s #/ var number "" var res ( ( 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" ) )   len for get 1 get number over / int number rot mod var number swap 2 get rot dup if for drop res over chain var res endfor else drop endif drop drop endfor drop res enddef   1968 romanEnc print
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.
#Red
Red
Red [ Purpose: "Arabic <-> Roman numbers converter" Author: "Didier Cadieu" Date: "07-Oct-2016" ]   table-r2a: reverse [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-to-arabic: func [r [string!] /local a b e] [ a: 0 parse r [any [b: ["I" ["V" | "X" | none] | "X" ["L" | "C" | none] | "C" ["D" | "M" | none] | "V" | "L" | "D" | "M"] e: (a: a + select table-r2a copy/part b e)]] a ]   ; Example usage: print roman-to-arabic "XXXIII" print roman-to-arabic "MDCCCLXXXVIII" print roman-to-arabic "MMXVI"  
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
#BBC_BASIC
BBC BASIC
PRINT STRING$(5, "ha")
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
#beeswax
beeswax
p < p0~1<}~< d@< _VT@1~>yg~9PKd@M'd;
http://rosettacode.org/wiki/Return_multiple_values
Return multiple values
Task Show how to return more than one value from a function.
#Eiffel
Eiffel
some_feature: TUPLE do Result := [1, 'j', "r"] end
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).
#Aime
Aime
index x;   list(1, 2, 3, 1, 2, 3, 4, 1).ucall(i_add, 1, x, 0); x.i_vcall(o_, 1, " "); o_newline();
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.
#Ada
Ada
with Ada.Text_IO, Ada.Directories, Ada.Command_Line, Ada.IO_Exceptions; use Ada.Text_IO;   procedure Remove_Lines_From_File is Temporary: constant String := ".tmp"; begin if Ada.Command_Line.Argument_Count /= 3 then raise Constraint_Error; end if; declare Filename: String := Ada.Command_Line.Argument(1); First: Positive := Integer'Value(Ada.Command_Line.Argument(2)); Last: Natural := Integer'Value(Ada.Command_Line.Argument(3)) + First - 1; Input, Output: File_Type; Line_Number: Positive := 1; begin Open(Input, In_File, Filename); -- open original file for reading Create(Output, Out_File, Filename & Temporary); -- write to temp. file while not End_Of_File(Input) loop declare Line: String := Get_Line(Input); begin if Line_Number < First or else Line_Number > Last then Put_Line(Output, Line); end if; end; Line_Number := Line_Number + 1; end loop; Close(Input); Close(Output); Ada.Directories.Rename(Old_Name => Filename & Temporary, New_Name => Filename); end; exception when Constraint_Error | Ada.IO_Exceptions.Name_Error => Put_Line("usage: " & Ada.Command_Line.Command_Name & " <filename> <first> <length>"); Put_Line(" opens <filename> for reading and " & "<filename>" & Temporary & " for temporary writing"); Put_Line(" requires first > 0, length >= 0"); end Remove_Lines_From_File;
http://rosettacode.org/wiki/Record_sound
Record sound
Record a monophonic 16-bit PCM sound into either memory space, a file or array. (This task neglects to specify the sample rate, and whether to use signed samples. The programs in this page might use signed 16-bit or unsigned 16-bit samples, at 8000 Hz, 44100 Hz, or any other sample rate. Therefore, these programs might not record sound in the same format.)
#BBC_BASIC
BBC BASIC
wavfile$ = @dir$ + "capture.wav" bitspersample% = 16 channels% = 2 samplespersec% = 44100   alignment% = bitspersample% * channels% / 8 bytespersec% = alignment% * samplespersec%   params$ = " bitspersample " + STR$(bitspersample%) + \ \ " channels " + STR$(channels%) + \ \ " alignment " + STR$(alignment%) + \ \ " samplespersec " + STR$(samplespersec%) + \ \ " bytespersec " + STR$(bytespersec%)   SYS "mciSendString", "close all", 0, 0, 0 SYS "mciSendString", "open new type waveaudio alias capture", 0, 0, 0 SYS "mciSendString", "set capture" + params$, 0, 0, 0 TO res% IF res% ERROR 100, "Couldn't set capture parameters: " + STR$(res% AND &FFFF)   PRINT "Press SPACE to start recording..." REPEAT UNTIL INKEY(1) = 32   SYS "mciSendString", "record capture", 0, 0, 0 TO res% IF res% ERROR 100, "Couldn't start audio capture: " + STR$(res% AND &FFFF)   PRINT "Recording, press SPACE to stop..." REPEAT UNTIL INKEY(1) = 32   SYS "mciSendString", "stop capture", 0, 0, 0 SYS "mciSendString", "save capture " + wavfile$, 0, 0, 0 TO res% IF res% ERROR 100, "Couldn't save to WAV file: " + STR$(res% AND &FFFF)   SYS "mciSendString", "delete capture", 0, 0, 0 SYS "mciSendString", "close capture", 0, 0, 0   PRINT "Captured audio is stored in " wavfile$
http://rosettacode.org/wiki/Record_sound
Record sound
Record a monophonic 16-bit PCM sound into either memory space, a file or array. (This task neglects to specify the sample rate, and whether to use signed samples. The programs in this page might use signed 16-bit or unsigned 16-bit samples, at 8000 Hz, 44100 Hz, or any other sample rate. Therefore, these programs might not record sound in the same format.)
#C
C
#include <stdlib.h> #include <unistd.h> #include <sys/types.h> #include <fcntl.h>   void * record(size_t bytes) { int fd; if (-1 == (fd = open("/dev/dsp", O_RDONLY))) return 0; void *a = malloc(bytes); read(fd, a, bytes); close(fd); return a; }   int play(void *buf, size_t len) { int fd; if (-1 == (fd = open("/dev/dsp", O_WRONLY))) return 0; write(fd, buf, len); close(fd); return 1; }   int main() { void *p = record(65536); play(p, 65536); return 0; }
http://rosettacode.org/wiki/Reflection/List_methods
Reflection/List methods
Task The goal is to get the methods of an object, as names, values or both. Some languages offer dynamic methods, which in general can only be inspected if a class' public API includes a way of listing them.
#Go
Go
package main   import ( "fmt" "image" "reflect" )   type t int // A type definition   // Some methods on the type func (r t) Twice() t { return r * 2 } func (r t) Half() t { return r / 2 } func (r t) Less(r2 t) bool { return r < r2 } func (r t) privateMethod() {}   func main() { report(t(0)) report(image.Point{}) }   func report(x interface{}) { v := reflect.ValueOf(x) t := reflect.TypeOf(x) // or v.Type() n := t.NumMethod() fmt.Printf("Type %v has %d exported methods:\n", t, n) const format = "%-6s %-46s %s\n" fmt.Printf(format, "Name", "Method expression", "Method value") for i := 0; i < n; i++ { fmt.Printf(format, t.Method(i).Name, t.Method(i).Func.Type(), v.Method(i).Type(), ) } fmt.Println() }
http://rosettacode.org/wiki/Reflection/List_properties
Reflection/List properties
Task The goal is to get the properties of an object, as names, values or both. Some languages support dynamic properties, which in general can only be inspected if a class' public API includes a way of listing them.
#Julia
Julia
for obj in (Int, 1, 1:10, collect(1:10), now()) println("\nObject: $obj\nDescription:") dump(obj) end
http://rosettacode.org/wiki/Reflection/List_properties
Reflection/List properties
Task The goal is to get the properties of an object, as names, values or both. Some languages support dynamic properties, which in general can only be inspected if a class' public API includes a way of listing them.
#Kotlin
Kotlin
// version 1.1   import kotlin.reflect.full.memberProperties import kotlin.reflect.jvm.isAccessible   open class BaseExample(val baseProp: String) { protected val protectedProp: String = "inherited protected value" }   class Example(val prop1: String, val prop2: Int, baseProp: String) : BaseExample(baseProp) { private val privateProp: String = "private value"   val prop3: String get() = "property without backing field"   val prop4 by lazy { "delegated value" } }   fun main(args: Array<String>) { val example = Example(prop1 = "abc", prop2 = 1, baseProp = "inherited public value") val props = Example::class.memberProperties for (prop in props) { prop.isAccessible = true // makes non-public properties accessible println("${prop.name.padEnd(13)} -> ${prop.get(example)}") } }
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
#C
C
  #include <stdio.h> #include <string.h>   int repstr(char *str) { if (!str) return 0;   size_t sl = strlen(str) / 2; while (sl > 0) { if (strstr(str, str + sl) == str) return sl; --sl; }   return 0; }   int main(void) { char *strs[] = { "1001110011", "1110111011", "0010010010", "1111111111", "0100101101", "0100100", "101", "11", "00", "1" };   size_t strslen = sizeof(strs) / sizeof(strs[0]); size_t i; for (i = 0; i < strslen; ++i) { int n = repstr(strs[i]); if (n) printf("\"%s\" = rep-string \"%.*s\"\n", strs[i], n, strs[i]); else printf("\"%s\" = not a rep-string\n", strs[i]); }   return 0; }  
http://rosettacode.org/wiki/Reflection/Get_source
Reflection/Get source
Task The goal is to get the source code or file path and line number where a programming object (e.g. module, class, function, method) is defined.
#Wren
Wren
import "os" for Platform, Process import "io" for File import "/pattern" for Pattern   var getSourceLines = Fn.new { var fileName = Process.allArguments[1] var text = File.read(fileName) var sep = Platform.isWindows ? "\r\n" : "\n" return [fileName, text.split(sep)] }   var res = getSourceLines.call() var fileName = res[0] var lines = res[1] // look for getSourceLines function var funcName = "getSourceLines" var p = Pattern.new("+1/s") var i = 1 var found = 0 for (line in lines) { var t = p.splitAll(line.trim()) if (t[0] == "var" && t[1] == funcName && t[2] == "=" && t[3] == "Fn.new") { found = i break } i = i + 1 }   System.print("File name  : %(fileName)") System.print("Function name : %(funcName)") System.print("Line number  : %(found > 0 ? found : "Function not found")")
http://rosettacode.org/wiki/Reflection/Get_source
Reflection/Get source
Task The goal is to get the source code or file path and line number where a programming object (e.g. module, class, function, method) is defined.
#zkl
zkl
src:=File(__FILE__).read(); println("Src file is \"%s\" and has %d lines".fmt(__FILE__,src.len(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
#C.23
C#
using System; using System.Text.RegularExpressions;   class Program { static void Main(string[] args) { string str = "I am a string";   if (new Regex("string$").IsMatch(str)) { Console.WriteLine("Ends with string."); }   str = new Regex(" a ").Replace(str, " another "); Console.WriteLine(str); } }
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
#Amazing_Hopper
Amazing Hopper
  #include <hopper.h>   main: s="mañana será otro día" reverse(s),strtoutf8, println {0}return  
http://rosettacode.org/wiki/Rendezvous
Rendezvous
Demonstrate the “rendezvous” communications technique by implementing a printer monitor.
#Wren
Wren
class Printer { construct new(id, ink) { _id = id _ink = ink }   ink { _ink } ink=(v) { _ink = v }   print(text) { System.write("%(_id): ") for (c in text) System.write(c) System.print() _ink = _ink - 1 } }   var ptrMain = Printer.new("Main ", 5) var ptrReserve = Printer.new("Reserve", 5)   var hd = [ "Humpty Dumpty sat on a wall.", "Humpty Dumpty had a great fall.", "All the king's horses and all the king's men", "Couldn't put Humpty together again." ]   var mg = [ "Old Mother Goose", "When she wanted to wander,", "Would ride through the air", "On a very fine gander.", "Jack's mother came in,", "And caught the goose soon,", "And mounting its back,", "Flew up to the moon." ]   var task = Fn.new { |name| var lines = (name == "Humpty Dumpty") ? hd : mg for (line in lines) { if (ptrMain.ink > 0) { ptrMain.print(line) Fiber.yield() } else if (ptrReserve.ink > 0) { ptrReserve.print(line) Fiber.yield() } else { Fiber.abort("ERROR  : Reserve printer ran out of ink in %(name) task.") } } }   var rhymes = ["Humpty Dumpty", "Mother Goose"] var tasks = List.filled(2, null) for (i in 0..1) { tasks[i] = Fiber.new(task) tasks[i].call(rhymes[i]) }   while (true) { for (i in 0..1) { if (!tasks[i].isDone) { var error = tasks[i].try() if (error) { System.print(error) return } } } if (tasks.all { |task| task.isDone }) return }
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.
#Factor
Factor
3 [ "Hello!" print ] times
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.
#Forth
Forth
: times ( xt n -- ) 0 ?do dup execute loop drop ;
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.)
#DCL
DCL
rename input.txt output.txt rename docs.dir mydocs.dir rename [000000]input.txt [000000]output.txt rename [000000]docs.dir [000000]mydocs.dir
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.)
#Delphi
Delphi
program RenameFile;   {$APPTYPE CONSOLE}   uses SysUtils;   begin SysUtils.RenameFile('input.txt', 'output.txt'); SysUtils.RenameFile('\input.txt', '\output.txt');   // RenameFile works for both files and folders SysUtils.RenameFile('docs', 'MyDocs'); SysUtils.RenameFile('\docs', '\MyDocs'); end.
http://rosettacode.org/wiki/Resistor_mesh
Resistor mesh
Task Given   10×10   grid nodes   (as shown in the image)   interconnected by   1Ω   resistors as shown, find the resistance between points   A   and   B. See also   (humor, nerd sniping)   xkcd.com cartoon
#REXX
REXX
/*REXX program calculates the resistance between any two points on a resistor grid.*/ if 2=='f2'x then ohms = "ohms" /*EBCDIC machine? Then use 'ohms'. */ else ohms = "Ω" /* ASCII " " " Greek Ω.*/ parse arg high wide Arow Acol Brow Bcol digs . /*obtain optional arguments from the CL*/ if high=='' | high=="," then high= 10 /*Not specified? Then use the default.*/ if wide=='' | wide=="," then wide= 10 /* " " " " " " */ if Arow=='' | Arow=="," then Arow= 2 /* " " " " " " */ if Acol=='' | Acol=="," then Acol= 2 /* " " " " " " */ if Brow=='' | Brow=="," then Brow= 7 /* " " " " " " */ if Bcol=='' | Bcol=="," then Bcol= 8 /* " " " " " " */ if digs=='' | digs=="," then digs= 20 /* " " " " " " */ numeric digits digs /*use moderate decimal digs (precision)*/ minVal = 1'e-' || (digs*2) /*calculate the threshold minimal value*/ say ' minimum value is ' format(minVal,,,,0) " using " digs ' decimal digits'; say say ' resistor mesh size is: ' wide "wide, " high 'high'  ; say say ' point A is at (row,col): ' Arow"," Acol say ' point B is at (row,col): ' Brow"," Bcol @.=0; cell.= 1 do until $<=minVal; v= 0 @.Arow.Acol= 1  ; cell.Arow.Acol= 0 @.Brow.Bcol= '-1' ; cell.Brow.Bcol= 0 $=0 do i=1 for high; im= i-1; ip= i+1 do j=1 for wide; n= 0; v= 0 if i\==1 then do; v= v + @.im.j; n= n+1; end if j\==1 then do; jm= j-1; v= v + @.i.jm; n= n+1; end if i<high then do; v= v + @.ip.j; n= n+1; end if j<wide then do; jp= j+1; v= v + @.i.jp; n= n+1; end v= @.i.j - v / n; #.i.j= v; if cell.i.j then $= $ + v*v end /*j*/ end /*i*/ do r=1 for High do c=1 for Wide; @.r.c= @.r.c - #.r.c end /*c*/ end /*r*/ end /*until*/ say Acur= #.Arow.Acol * sides(Arow, Acol) Bcur= #.Brow.Bcol * sides(Brow, Bcol) say ' resistance between point A and point B is: ' 4 / (Acur - Bcur) ohms exit /*stick a fork in it, we're all done. */ /*──────────────────────────────────────────────────────────────────────────────────────*/ sides: parse arg row,col; z=0; if row\==1 & row\==high then z= z+2; else z= z+1 if col\==1 & col\==wide then z= z+2; else z= z+1 return z
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
#F.23
F#
  //Reverse words in a string. Nigel Galloway: July 14th., 2021 [" ---------- Ice and Fire ------------ "; " "; " fire, in end will world the say Some "; " ice. in say Some "; " desire of tasted I've what From "; " fire. favour who those with hold I "; " "; " ... elided paragraph last ... "; " "; " Frost Robert ----------------------- "]|>List.map(fun n->n.Split " "|>Array.filter((<>)"")|>Array.rev|>String.concat " ")|>List.iter(printfn "%s")  
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
#PostScript
PostScript
  /r13 { 4 dict begin /rotc { { {{{64 gt} {91 lt}} all?} {65 - 13 + 26 mod 65 +} is? {{{95 gt} {123 lt}} all?} {97 - 13 + 26 mod 97 +} is? } cond }. {rotc} map cvstr 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
#PHP
PHP
  /** * int2roman * Convert any positive value of a 32-bit signed integer to its modern roman * numeral representation. Numerals within parentheses are multiplied by * 1000. ie. M == 1 000, (M) == 1 000 000, ((M)) == 1 000 000 000 * * @param number - an integer between 1 and 2147483647 * @return roman numeral representation of number */ function int2roman($number) { if (!is_int($number) || $number < 1) return false; // ignore negative numbers and zero   $integers = array(900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1); $numerals = array('CM', 'D', 'CD', 'C', 'XC', 'L', 'XL', 'X', 'IX', 'V', 'IV', 'I'); $major = intval($number / 1000) * 1000; $minor = $number - $major; $numeral = $leastSig = '';   for ($i = 0; $i < sizeof($integers); $i++) { while ($minor >= $integers[$i]) { $leastSig .= $numerals[$i]; $minor -= $integers[$i]; } }   if ($number >= 1000 && $number < 40000) { if ($major >= 10000) { $numeral .= '('; while ($major >= 10000) { $numeral .= 'X'; $major -= 10000; } $numeral .= ')'; } if ($major == 9000) { $numeral .= 'M(X)'; return $numeral . $leastSig; } if ($major == 4000) { $numeral .= 'M(V)'; return $numeral . $leastSig; } if ($major >= 5000) { $numeral .= '(V)'; $major -= 5000; } while ($major >= 1000) { $numeral .= 'M'; $major -= 1000; } }   if ($number >= 40000) { $major = $major/1000; $numeral .= '(' . int2roman($major) . ')'; }   return $numeral . $leastSig; }  
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.
#REXX
REXX
/* Rexx */   Do /* 1990 2008 1666 */ years = 'MCMXC MMVIII MDCLXVI'   Do y_ = 1 to words(years) Say right(word(years, y_), 10) || ':' decode(word(years, y_)) End y_   Return End Exit   decode: Procedure Do Parse upper arg roman .   If verify(roman, 'MDCLXVI') = 0 then Do   /* always insert the value of the least significant numeral */ decnum = rchar(substr(roman, length(roman), 1)) Do d_ = 1 to length(roman) - 1 If rchar(substr(roman, d_, 1)) < rchar(substr(roman, d_ + 1, 1)) then Do /* Handle cases where numerals are not in descending order */ /* subtract the value of the numeral */ decnum = decnum - rchar(substr(roman, d_, 1)) End else Do /* Normal case */ /* add the value of the numeral */ decnum = decnum + rchar(substr(roman, d_, 1)) End End d_ End else Do decnum = roman 'contains invalid roman numerals' End   Return decnum End Exit   rchar: Procedure Do Parse upper arg ch +1 .   select when ch = 'M' then digit = 1000 when ch = 'D' then digit = 500 when ch = 'C' then digit = 100 when ch = 'L' then digit = 50 when ch = 'X' then digit = 10 when ch = 'V' then digit = 5 when ch = 'I' then digit = 1 otherwise digit = 0 end   Return digit End Exit
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
#Befunge
Befunge
v> ">:#,_v >29*+00p>~:"0"- #v_v $ v ^p0p00:-1g00< $ > v p00&p0-1g00+4*65< >00g1-:00p#^_@
http://rosettacode.org/wiki/Return_multiple_values
Return multiple values
Task Show how to return more than one value from a function.
#Elena
Elena
import system'routines; import extensions;   extension op { MinMax(ref int minVal, ref int maxVal) { var ordered := self.ascendant();   minVal := ordered.FirstMember; maxVal := ordered.LastMember } }   public program() { var values := new int[]{4, 51, 1, -3, 3, 6, 8, 26, 2, 4};   values.MinMax(ref int min, ref int max);   console.printLine("Min: ",min," Max: ",max) }
http://rosettacode.org/wiki/Return_multiple_values
Return multiple values
Task Show how to return more than one value from a function.
#Elixir
Elixir
defmodule RC do def addsub(a, b) do {a+b, a-b} end end   {add, sub} = RC.addsub(7, 4) IO.puts "Add: #{add},\tSub: #{sub}"
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).
#ALGOL_68
ALGOL 68
# use the associative array in the Associate array/iteration task # # this example uses strings - for other types, the associative # # array modes AAELEMENT and AAKEY should be modified as required # PR read "aArray.a68" PR   # returns the unique elements of list # PROC remove duplicates = ( []STRING list )[]STRING: BEGIN REF AARRAY elements := INIT LOC AARRAY; INT count := 0; FOR pos FROM LWB list TO UPB list DO IF NOT ( elements CONTAINSKEY list[ pos ] ) THEN # first occurance of this element # elements // list[ pos ] := ""; count +:= 1 FI OD; # construct an array of the unique elements from the # # associative array - the new list will not necessarily be # # in the original order # [ count ]STRING result; REF AAELEMENT e := FIRST elements; FOR pos WHILE e ISNT nil element DO result[ pos ] := key OF e; e := NEXT elements OD; result END; # remove duplicates #   # test the duplicate removal # print( ( remove duplicates( ( "A", "B", "D", "A", "C", "F", "F", "A" ) ), newline ) )  
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.
#ALGOL_68
ALGOL 68
# removes the specified number of lines from a file, starting at start line (numbered from 1) # # returns TRUE if successful, FALSE otherwise # PROC remove lines = ( STRING file name, INT start line, INT number of lines )BOOL: IF number of lines < 0 OR start line < 1 THEN # invalid parameters # print( ( "number of lines must be >= 0 and start line must be >= 1", newline ) ); FALSE ELIF FILE temp file; create( temp file, stand back channel ) /= 0 THEN # unable to create a temporary output file # print( ( "Unable to create temporary file", newline ) ); FALSE ELIF NOT reset possible( temp file ) THEN # rewinding the temporary file is not possible # # we would have to get its name ( with "idf( temp file )", close it and re-open it # print( ( "Temp file is not rewindable", newline ) ); FALSE ELIF FILE input file; open( input file, file name, stand in channel ) /= 0 THEN # failed to open the file # print( ( "Unable to open """ + file name + """", newline ) ); FALSE ELSE # files opened OK # BOOL at eof := FALSE; # set the EOF handler for the original file # on logical file end( input file , ( REF FILE f )BOOL: BEGIN # note that we reached EOF on the latest read # at eof := TRUE; # return TRUE so processing can continue # TRUE END ); # copy the input file to the temp file # WHILE STRING line; get( input file, ( line, newline ) ); NOT at eof DO put( temp file, ( line, newline ) ) OD; # copy the temp file back to the input, removing the specified lines # close( input file ); IF open( input file, file name, stand out channel ) /= 0 THEN # failed to open the original file for output # print( ( "Unable to open ", file name, " for output", newline ) ); FALSE ELSE # opened OK - copy the temporary file # reset( temp file ); # rewinds the input file # at eof := FALSE; on logical file end( temp file , ( REF FILE f )BOOL: BEGIN # note that we reached EOF on the latest read # at eof := TRUE; # return TRUE so processing can continue # TRUE END ); INT end line = ( start line - 1 ) + number of lines; INT line number := 0; WHILE STRING line; get( temp file, ( line, newline ) ); NOT at eof DO # have another line # line number +:= 1; IF line number < start line OR line number > end line THEN put( input file, ( line, newline ) ) FI OD; # close the files # close( input file ); scratch( temp file ); IF line number < start line THEN # didn't find the start line # print( ( "Specified start line (", whole( start line, 0 ), ") not in ", file name, newline ) ); FALSE ELIF line number < end line THEN # the ending line was not in the file # print( ( "Final omitted line not in the file ", file name, newline ) ); FALSE ELSE # successful operation # TRUE FI FI FI # remove lines # ;   # test the line removal # BEGIN FILE t; open( t, "test.txt", stand out channel ); print( ( "Before...", newline ) ); FOR i TO 10 DO STRING line = whole( i, - ( ( i MOD 5 ) + 3 ) ); put( t, ( line, newline ) ); print( ( line, newline ) ) OD; close( t ); remove lines( "test.txt", 2, 3 ); print( ( "After...", newline ) ); open( t, "test.txt", stand in channel ); FOR i TO 7 DO STRING line; get( t, ( line, newline ) ); print( ( line, newline ) ) OD; close( t ); print( ( "----", newline ) ) END
http://rosettacode.org/wiki/Record_sound
Record sound
Record a monophonic 16-bit PCM sound into either memory space, a file or array. (This task neglects to specify the sample rate, and whether to use signed samples. The programs in this page might use signed 16-bit or unsigned 16-bit samples, at 8000 Hz, 44100 Hz, or any other sample rate. Therefore, these programs might not record sound in the same format.)
#C.2B.2B
C++
  #include <iostream> #include <string> #include <windows.h> #include <mmsystem.h>   #pragma comment ( lib, "winmm.lib" ) using namespace std;   class recorder { public: void start() { paused = rec = false; action = "IDLE"; while( true ) { cout << endl << "==" << action << "==" << endl << endl; cout << "1) Record" << endl << "2) Play" << endl << "3) Pause" << endl << "4) Stop" << endl << "5) Quit" << endl; char c; cin >> c; if( c > '0' && c < '6' ) { switch( c ) { case '1': record(); break; case '2': play(); break; case '3': pause(); break; case '4': stop(); break; case '5': stop(); return; } } } } private: void record() { if( mciExecute( "open new type waveaudio alias my_sound") ) { mciExecute( "record my_sound" ); action = "RECORDING"; rec = true; } } void play() { if( paused ) mciExecute( "play my_sound" ); else if( mciExecute( "open tmp.wav alias my_sound" ) ) mciExecute( "play my_sound" );   action = "PLAYING"; paused = false; } void pause() { if( rec ) return; mciExecute( "pause my_sound" ); paused = true; action = "PAUSED"; } void stop() { if( rec ) { mciExecute( "stop my_sound" ); mciExecute( "save my_sound tmp.wav" ); mciExecute( "close my_sound" ); action = "IDLE"; rec = false; } else { mciExecute( "stop my_sound" ); mciExecute( "close my_sound" ); action = "IDLE"; } } bool mciExecute( string cmd ) { if( mciSendString( cmd.c_str(), NULL, 0, NULL ) ) { cout << "Can't do this: " << cmd << endl; return false; } return true; }   bool paused, rec; string action; };   int main( int argc, char* argv[] ) { recorder r; r.start(); return 0; }  
http://rosettacode.org/wiki/Reflection/List_methods
Reflection/List methods
Task The goal is to get the methods of an object, as names, values or both. Some languages offer dynamic methods, which in general can only be inspected if a class' public API includes a way of listing them.
#J
J
  NB. define a stack class coclass 'Stack' create =: 3 : 'items =: i. 0' push =: 3 : '# items =: items , < y' top =: 3 : '> {: items' pop =: 3 : ([;._2' a =. top 0; items =: }: items; a;') destroy =: codestroy cocurrent 'base'   names_Stack_'' NB. all names create destroy pop push top   'p' names_Stack_ 3 NB. verbs that start with p pop push     NB. make an object. The dyadic definition of cownew invokes the create verb S =: conew~ 'Stack'   names__S'' NB. object specific names COCREATOR items     pop__S NB. introspection: get the verbs definition 3 : 0 a =. top 0 items =: }: items a )     NB. get the search path of object S copath S ┌─────┬─┐ │Stack│z│ └─────┴─┘     names__S 0 NB. get the object specific data COCREATOR items    
http://rosettacode.org/wiki/Reflection/List_methods
Reflection/List methods
Task The goal is to get the methods of an object, as names, values or both. Some languages offer dynamic methods, which in general can only be inspected if a class' public API includes a way of listing them.
#Java
Java
import java.lang.reflect.Method;   public class ListMethods { public int examplePublicInstanceMethod(char c, double d) { return 42; }   private boolean examplePrivateInstanceMethod(String s) { return true; }   public static void main(String[] args) { Class clazz = ListMethods.class;   System.out.println("All public methods (including inherited):"); for (Method m : clazz.getMethods()) { System.out.println(m); } System.out.println(); System.out.println("All declared methods (excluding inherited):"); for (Method m : clazz.getDeclaredMethods()) { System.out.println(m); } } }
http://rosettacode.org/wiki/Reflection/List_properties
Reflection/List properties
Task The goal is to get the properties of an object, as names, values or both. Some languages support dynamic properties, which in general can only be inspected if a class' public API includes a way of listing them.
#Lingo
Lingo
obj = script("MyClass").new() obj.foo = 23 obj.bar = 42   -- ...   -- show obj's property names and values cnt = obj.count repeat with i = 1 to cnt put obj.getPropAt(i)&" = "&obj[i] end repeat
http://rosettacode.org/wiki/Reflection/List_properties
Reflection/List properties
Task The goal is to get the properties of an object, as names, values or both. Some languages support dynamic properties, which in general can only be inspected if a class' public API includes a way of listing them.
#Lua
Lua
a = 1 b = 2.0 c = "hello world"   function listProperties(t) if type(t) == "table" then for k,v in pairs(t) do if type(v) ~= "function" then print(string.format("%7s: %s", type(v), k)) end end end end   print("Global properties") listProperties(_G) print("Package properties") listProperties(package)
http://rosettacode.org/wiki/Reflection/List_properties
Reflection/List properties
Task The goal is to get the properties of an object, as names, values or both. Some languages support dynamic properties, which in general can only be inspected if a class' public API includes a way of listing them.
#Nanoquery
Nanoquery
// declare a class that has fields to be listed class Fields declare static field1 = "this is a static field. it will not be listed" declare field2 declare field3 declare field4 end   // list all the fields in the class for fieldname in Fields.getFieldNames() println fieldname 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
#C.2B.2B
C++
#include <string> #include <vector> #include <boost/regex.hpp>   bool is_repstring( const std::string & teststring , std::string & repunit ) { std::string regex( "^(.+)\\1+(.*)$" ) ; boost::regex e ( regex ) ; boost::smatch what ; if ( boost::regex_match( teststring , what , e , boost::match_extra ) ) { std::string firstbracket( what[1 ] ) ; std::string secondbracket( what[ 2 ] ) ; if ( firstbracket.length( ) >= secondbracket.length( ) && firstbracket.find( secondbracket ) != std::string::npos ) { repunit = firstbracket ; } } return !repunit.empty( ) ; }   int main( ) { std::vector<std::string> teststrings { "1001110011" , "1110111011" , "0010010010" , "1010101010" , "1111111111" , "0100101101" , "0100100" , "101" , "11" , "00" , "1" } ; std::string theRep ; for ( std::string myString : teststrings ) { if ( is_repstring( myString , theRep ) ) { std::cout << myString << " is a rep string! Here is a repeating string:\n" ; std::cout << theRep << " " ; } else { std::cout << myString << " is no rep string!" ; } theRep.clear( ) ; std::cout << std::endl ; } return 0 ; }
http://rosettacode.org/wiki/Regular_expressions
Regular expressions
Task   match a string against a regular expression   substitute part of a string using a regular expression
#C.2B.2B
C++
#include <iostream> #include <string> #include <iterator> #include <regex>   int main() { std::regex re(".* string$"); std::string s = "Hi, I am a string";   // match the complete string if (std::regex_match(s, re)) std::cout << "The string matches.\n"; else std::cout << "Oops - not found?\n";   // match a substring std::regex re2(" a.*a"); std::smatch match; if (std::regex_search(s, match, re2)) { std::cout << "Matched " << match.length() << " characters starting at " << match.position() << ".\n"; std::cout << "Matched character sequence: \"" << match.str() << "\"\n"; } else { std::cout << "Oops - not found?\n"; }   // replace a substring std::string dest_string; std::regex_replace(std::back_inserter(dest_string), s.begin(), s.end(), re2, "'m now a changed"); std::cout << dest_string << std::endl; }
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
#Apex
Apex
  String str = 'Hello World!'; str = str.reverse(); system.debug(str);  
http://rosettacode.org/wiki/Rendezvous
Rendezvous
Demonstrate the “rendezvous” communications technique by implementing a printer monitor.
#zkl
zkl
class OutOfInk(Exception.IOError){ const TEXT="Out of ink"; text=TEXT; // rename IOError to OutOfInk for this first/mother class fcn init{ IOError.init(TEXT) } // this renames instances } class Printer{ var id, ink; fcn init(_id,_ink){ id,ink=vm.arglist } fcn print(line){ if(not ink) throw(OutOfInk); println("%s: %s".fmt(id,line)); Atomic.sleep((0.0).random(0.01)); // don't let one thread dominate ink-=1; } } class RendezvousPrinter{ // the choke point between printers and tasks var printers=Thread.List(); // a thread safe list fcn init(_printers){ printers.extend(vm.arglist) } fcn print(line){ // caller waits for print job to finish var lines=Thread.List(); // fcn local [static] variable, the print queue lines.write(line); // thread safe, stalls when full // lines is racy - other threads are modifing it, length is suspect here while(True){ // this thread can print that threads job critical{ // creates a [global] mutex, automatically unlocks on exception if(not printers) throw(OutOfInk); // No more printers to try if(not lines) break; // only remove jobs in this serialized section try{ printers[0].print(lines[0]); // can throw lines.del(0); // successful print, remove job from queue }catch(OutOfInk){ printers.del(0) } // Switch to the next printer } } } }
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.
#FreeBASIC
FreeBASIC
' FB 1.05.0 Win64   Sub proc() Print " proc called" End Sub   Sub repeat(s As Sub, n As UInteger) For i As Integer = 1 To n Print Using "##"; i; s() Next End Sub   repeat(@proc, 5) Print Print "Press any key to quit" Sleep
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.)
#E
E
for where in [<file:.>, <file:///>] { where["input.txt"].renameTo(where["output.txt"], null) where["docs"].renameTo(where["mydocs"], null) }
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.)
#Elixir
Elixir
File.rename "input.txt","output.txt" File.rename "docs", "mydocs" File.rename "/input.txt", "/output.txt" File.rename "/docs", "/mydocs"
http://rosettacode.org/wiki/Resistor_mesh
Resistor mesh
Task Given   10×10   grid nodes   (as shown in the image)   interconnected by   1Ω   resistors as shown, find the resistance between points   A   and   B. See also   (humor, nerd sniping)   xkcd.com cartoon
#Sidef
Sidef
var (w, h) = (10, 10)   var v = h.of { w.of(0) } # voltage var f = h.of { w.of(0) } # fixed condition var d = h.of { w.of(0) } # diff var n = [] # neighbors   for i in ^h { for j in (1 ..^ w ) { n[i][j] := [] << [i, j-1] } for j in (0 ..^ w-1) { n[i][j] := [] << [i, j+1] } }   for j in ^w { for i in (1 ..^ h ) { n[i][j] := [] << [i-1, j] } for i in (0 ..^ h-1) { n[i][j] := [] << [i+1, j] } }   func set_boundary { f[1][1] = 1; f[6][7] = -1; v[1][1] = 1; v[6][7] = -1; }   func calc_diff { var total_diff = 0 for i,j in (^h ~X ^w) { var w = n[i][j].map { |a| v.dig(a...) }.sum d[i][j] = (w = (v[i][j] - w/n[i][j].len)) f[i][j] || (total_diff += w*w) } total_diff }   func iter { var diff = 1 while (diff > 1e-24) { set_boundary() diff = calc_diff() for i,j in (^h ~X ^w) { v[i][j] -= d[i][j] } }   var current = 3.of(0) for i,j in (^h ~X ^w) { current[ f[i][j] ] += (d[i][j] * n[i][j].len) } (current[1] - current[-1]) / 2 }   say "R = #{2 / iter()}"
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
#Factor
Factor
USING: io sequences splitting ; IN: rosetta-code.reverse-words   "---------- 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 -----------------------"   "\n" split [ " " split reverse " " join ] map [ print ] each
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
#PowerBASIC
PowerBASIC
  #COMPILE EXE #COMPILER PBWIN 9.05 #DIM ALL   FUNCTION ROT13(BYVAL a AS STRING) AS STRING LOCAL p AS BYTE PTR LOCAL n AS BYTE, e AS BYTE LOCAL res AS STRING   res = a p = STRPTR(res) n = @p DO WHILE n SELECT CASE n CASE 65 TO 90 e = 90 n += 13 CASE 97 TO 122 e = 122 n += 13 CASE ELSE e = 255 END SELECT   IF n > e THEN n -= 26 END IF @p = n INCR p n = @p LOOP FUNCTION = res END FUNCTION   'testing:   FUNCTION PBMAIN () AS LONG #DEBUG PRINT ROT13("abc") #DEBUG PRINT ROT13("nop") END FUNCTION  
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
#Picat
Picat
go => List = [455,999,1990,1999,2000,2001,2008,2009,2010,2011,2012,1666,3456,3888,4000], foreach(Val in List) printf("%4d: %w\n", Val, roman_encode(Val)) end, nl.   roman_encode(Val) = Res => if Val <= 0 then Res := -1 else Arabic = [1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1], Roman = ["M", "CM", "D", "CD", "C", "XC","L","XL","X","IX","V","IV","I"], Res = "", foreach(I in 1..Arabic.length) while(Val >= Arabic[I]) Res := Res ++ Roman[I], Val := Val - Arabic[I] end end 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.
#Ring
Ring
  symbols = "MDCLXVI" weights = [1000,500,100,50,10,5,1]   see "MCMXCIX = " + romanDec("MCMXCIX") + nl see "MDCLXVI =" + romanDec("MDCLXVI") + nl see "XXV = " + romanDec("XXV") + nl see "CMLIV = " + romanDec("CMLIV") + nl see "MMXI = " + romanDec("MMXI") + nl   func romanDec roman n = 0 lastval = 0 arabic = 0 for i = len(roman) to 1 step -1 n = substr(symbols,roman[i]) if n > 0 n = weights[n] ok if n < lastval arabic = arabic - n else arabic = arabic + n ok lastval = n next return arabic  
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
#BQN
BQN
Repeat ← ×⟜≠ ⥊ ⊢   •Show 5 Repeat "Hello"
http://rosettacode.org/wiki/Return_multiple_values
Return multiple values
Task Show how to return more than one value from a function.
#Erlang
Erlang
% Put this code in return_multi.erl and run it as "escript return_multi.erl"   -module(return_multi).   main(_) -> {C, D, E} = multiply(3, 4), io:format("~p ~p ~p~n", [C, D, E]).   multiply(A, B) -> {A * B, A + B, A - B}.  
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).
#Amazing_Hopper
Amazing Hopper
  #include <hopper.h>   main: x=-1 {30} rand array (x), mulby(10), ceil, mov(x) {"Original Array:\n",x}, println {x}array(SORT), {x}sets(UNIQUE), mov(x) {"Final array:\n",x}, println   y={} {"C","Go","Go","C","Cobol","java","Ada"} pushall(y) {"java","algol-68","C","java","fortran"} pushall(y) {"\nOriginal Array:\n",y}, println {y}array(SORT), {y}sets(UNIQUE), mov(y) {"Final array:\n",y}, println exit(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.
#Amazing_Hopper
Amazing Hopper
  #include <hopper.h>   main: .ctrlc fd=0,fw=0 fopen(OPEN_READ,"archivo.txt")(fd) if file error? {"no pude abrir el archivo de lectura: "} jsub(show error) else fcreate(CREATE_NORMAL,"archivoTmp.txt")(fw) if file error? {"no pude crear el archivo para escritura: "} jsub(show error) else get arg number(2,desde), // from line get arg number(3,hasta), // to line   line read=0 while( not(feof(fd))) fread line(1000)(fd), ++line read if(not( {line read} between(desde, hasta))) {"\n"}cat,writeline(fw) endif wend endif endif fclose(fw) fclose(fd) system("mv archivoTmp.txt archivo.txt") exit(0) .locals show error: file error, println back  
http://rosettacode.org/wiki/Record_sound
Record sound
Record a monophonic 16-bit PCM sound into either memory space, a file or array. (This task neglects to specify the sample rate, and whether to use signed samples. The programs in this page might use signed 16-bit or unsigned 16-bit samples, at 8000 Hz, 44100 Hz, or any other sample rate. Therefore, these programs might not record sound in the same format.)
#ChucK
ChucK
// chuck this with other shreds to record to file // example> chuck foo.ck bar.ck rec   // arguments: rec:<filename>   // get name me.arg(0) => string filename; if( filename.length() == 0 ) "foo.wav" => filename;   // pull samples from the dac dac => Gain g => WvOut w => blackhole; // this is the output file name filename => w.wavFilename; <<<"writing to file:", "'" + w.filename() + "'">>>; // any gain you want for the output .5 => g.gain;   // temporary workaround to automatically close file on remove-shred null @=> w;   // infinite time loop... // ctrl-c will stop it, or modify to desired duration while( true ) 1::second => now;
http://rosettacode.org/wiki/Reflection/List_methods
Reflection/List methods
Task The goal is to get the methods of an object, as names, values or both. Some languages offer dynamic methods, which in general can only be inspected if a class' public API includes a way of listing them.
#JavaScript
JavaScript
// Sample classes for reflection function Super(name) { this.name = name; this.superOwn = function() { return 'super owned'; }; } Super.prototype = { constructor: Super className: 'super', toString: function() { return "Super(" + this.name + ")"; }, doSup: function() { return 'did super stuff'; } }   function Sub() { Object.getPrototypeOf(this).constructor.apply(this, arguments); this.rest = [].slice.call(arguments, 1); this.subOwn = function() { return 'sub owned'; }; } Sub.prototype = Object.assign( new Super('prototype'), { constructor: Sub className: 'sub', toString: function() { return "Sub(" + this.name + ")"; }, doSub: function() { return 'did sub stuff'; } });   Object.defineProperty(Sub.prototype, 'shush', { value: function() { return ' non-enumerable'; }, enumerable: false // the default });   var sup = new Super('sup'), sub = new Sub('sub', 0, 'I', 'two');   Object.defineProperty(sub, 'quiet', { value: function() { return 'sub owned non-enumerable'; }, enumerable: false });   // get enumerable methods on an object and its ancestors function get_method_names(obj) { var methods = []; for (var p in obj) { if (typeof obj[p] == 'function') { methods.push(p); } } return methods; }   get_method_names(sub); //["subOwn", "superOwn", "toString", "doSub", "doSup"]   // get enumerable properties on an object and its ancestors function get_property_names(obj) { var properties = []; for (var p in obj) { properties.push(p); } return properties; }   // alternate way to get enumerable method names on an object and its ancestors function get_method_names(obj) { return get_property_names(obj) .filter(function(p) {return typeof obj[p] == 'function';}); }   get_method_names(sub); //["subOwn", "superOwn", "toString", "doSub", "doSup"]   // get enumerable & non-enumerable method names set directly on an object Object.getOwnPropertyNames(sub) .filter(function(p) {return typeof sub[p] == 'function';}) //["subOwn", "shhh"]   // get enumerable method names set directly on an object Object.keys(sub) .filter(function(p) {return typeof sub[p] == 'function';}) //["subOwn"]   // get enumerable method names & values set directly on an object Object.entries(sub) .filter(function(p) {return typeof p[1] == 'function';}) //[["subOwn", function () {...}]]
http://rosettacode.org/wiki/Reflection/List_properties
Reflection/List properties
Task The goal is to get the properties of an object, as names, values or both. Some languages support dynamic properties, which in general can only be inspected if a class' public API includes a way of listing them.
#Nim
Nim
type Foo = object a: float b: string c: seq[int] let f = Foo(a: 0.9, b: "hi", c: @[1,2,3]) for n, v in f.fieldPairs: echo n, ": ", v
http://rosettacode.org/wiki/Reflection/List_properties
Reflection/List properties
Task The goal is to get the properties of an object, as names, values or both. Some languages support dynamic properties, which in general can only be inspected if a class' public API includes a way of listing them.
#Objective-C
Objective-C
#import <Foundation/Foundation.h> #import <objc/runtime.h>   @interface Foo : NSObject { int exampleIvar; } @property (nonatomic) double exampleProperty; @end @implementation Foo - (instancetype)init { self = [super init]; if (self) { exampleIvar = 42; _exampleProperty = 3.14; } return self; } @end   int main() { id obj = [[Foo alloc] init]; Class clazz = [obj class];   NSLog(@"\Instance variables:"); unsigned int ivarCount; Ivar *ivars = class_copyIvarList(clazz, &ivarCount); for (unsigned int i = 0; i < ivarCount; i++) { Ivar ivar = ivars[i]; const char *name = ivar_getName(ivar); const char *typeEncoding = ivar_getTypeEncoding(ivar); // for simple types we can use Key-Value Coding to access it // but in general we will have to use object_getIvar and cast it to the right type of function // corresponding to the type of the instance variable id value = [obj valueForKey:@(name)]; NSLog(@"%s\t%s\t%@", name, typeEncoding, value); } free(ivars);   NSLog(@""); NSLog(@"Properties:"); unsigned int propCount; objc_property_t *properties = class_copyPropertyList([Foo class], &propCount); for (unsigned int i = 0; i < propCount; i++) { objc_property_t p = properties[i]; const char *name = property_getName(p); const char *attributes = property_getAttributes(p); // for simple types we can use Key-Value Coding to access it // but in general we will have to use objc_msgSend to call the getter, // casting objc_msgSend to the right type of function corresponding to the type of the getter id value = [obj valueForKey:@(name)]; NSLog(@"%s\t%s\t%@", name, attributes, value); } free(properties);   return 0; }
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
#Clojure
Clojure
(defn rep-string [s] (let [len (count s) first-half (subs s 0 (/ len 2)) test-group (take-while seq (iterate butlast first-half)) test-reptd (map (comp #(take len %) cycle) test-group)] (some #(= (seq s) %) test-reptd)))
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
#Clojure
Clojure
(let [s "I am a string"] ;; match (when (re-find #"string$" s) (println "Ends with 'string'.")) (when-not (re-find #"^You" s) (println "Does not start with 'You'."))   ;; substitute (println (clojure.string/replace s " a " " another ")) )
http://rosettacode.org/wiki/Regular_expressions
Regular expressions
Task   match a string against a regular expression   substitute part of a string using a regular expression
#Common_Lisp
Common Lisp
(let ((string "I am a string")) (when (cl-ppcre:scan "string$" string) (write-line "Ends with string")) (unless (cl-ppcre:scan "^You" string ) (write-line "Does not start with 'You'")))
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
#APL
APL
⌽'asdf' fdsa
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.
#Gambas
Gambas
  Public Sub Main()   RepeatIt("RepeatableOne", 2)   RepeatIt("RepeatableTwo", 3)   End   'Cannot pass procedure pointer in Gambas; must pass procedure name and use Object.Call() Public Sub RepeatIt(sDelegateName As String, iCount As Integer)   For iCounter As Integer = 1 To iCount Object.Call(Me, sDelegateName, []) Next   End   Public Sub RepeatableOne()   Print "RepeatableOne"   End   Public Sub RepeatableTwo()   Print "RepeatableTwo"   End
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.)
#Emacs_Lisp
Emacs Lisp
(rename-file "input.txt" "output.txt") (rename-file "/input.txt" "/output.txt") (rename-file "docs" "mydocs") (rename-file "/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.)
#Erlang
Erlang
  file:rename("input.txt","output.txt"), file:rename( "docs", "mydocs" ), file:rename( "/input.txt", "/output.txt" ), file:rename( "/docs", "/mydocs" ).  
http://rosettacode.org/wiki/Resistor_mesh
Resistor mesh
Task Given   10×10   grid nodes   (as shown in the image)   interconnected by   1Ω   resistors as shown, find the resistance between points   A   and   B. See also   (humor, nerd sniping)   xkcd.com cartoon
#Tcl
Tcl
package require Tcl 8.6; # Or 8.5 with the TclOO package   # This code is structured as a class with a little trivial DSL parser # so it is easy to change what problem is being worked on. oo::class create ResistorMesh { variable forcePoints V fixed w h   constructor {boundaryConditions} { foreach {op condition} $boundaryConditions { switch $op { size { lassign $condition w h set fixed [lrepeat $h [lrepeat $w 0]] set V [lrepeat $h [lrepeat $w 0.0]] } fixed { lassign $condition j i v lset fixed $i $j [incr ctr] lappend forcePoints $j $i $v } } } }   method CalculateDifferences {*dV} { upvar 1 ${*dV} dV set error 0.0 for {set i 0} {$i < $h} {incr i} { for {set j 0} {$j < $w} {incr j} { set v 0.0 set n 0 if {$i} { set v [expr {$v + [lindex $V [expr {$i-1}] $j]}] incr n } if {$j} { set v [expr {$v + [lindex $V $i [expr {$j-1}]]}] incr n } if {$i+1 < $h} { set v [expr {$v + [lindex $V [expr {$i+1}] $j]}] incr n } if {$j+1 < $w} { set v [expr {$v + [lindex $V $i [expr {$j+1}]]}] incr n } lset dV $i $j [set v [expr {[lindex $V $i $j] - $v/$n}]] if {![lindex $fixed $i $j]} { set error [expr {$error + $v**2}] } } } return $error }   method FindCurrentFixpoint {epsilon} { set dV [lrepeat $h [lrepeat $w 0.0]] set current {0.0 0.0 0.0} while true { # Enforce the boundary conditions foreach {j i v} $forcePoints { lset V $i $j $v } # Compute the differences and the error set error [my CalculateDifferences dV] # Apply the differences for {set i 0} {$i < $h} {incr i} { for {set j 0} {$j < $w} {incr j} { lset V $i $j [expr { [lindex $V $i $j] - [lindex $dV $i $j]}] } } # Done if the error is small enough if {$error < $epsilon} break } # Compute the currents from the error for {set i 0} {$i < $h} {incr i} { for {set j 0} {$j < $w} {incr j} { lset current [lindex $fixed $i $j] [expr { [lindex $current [lindex $fixed $i $j]] + [lindex $dV $i $j] * (!!$i+!!$j+($i<$h-1)+($j<$w-1))}] } } # Compute the actual current flowing between source and sink return [expr {([lindex $current 1] - [lindex $current 2]) / 2.0}] }   # Public entry point method solveForResistance {{epsilon 1e-24}} { set voltageDifference [expr { [lindex $forcePoints 2] - [lindex $forcePoints 5]}] expr {$voltageDifference / [my FindCurrentFixpoint $epsilon]} } }
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
#Forth
Forth
: not-empty? dup 0 > ; : (reverse) parse-name not-empty? IF recurse THEN type space ; : reverse (reverse) cr ;   reverse ---------- Ice and Fire ------------ reverse reverse fire, in end will world the say Some reverse ice. in say Some reverse desire of tasted I've what From reverse fire. favor who those with hold I reverse reverse ... elided paragraph last ... reverse reverse 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
#Fortran
Fortran
  character*40 words character*40 reversed logical inblank ierr=0 read (5,fmt="(a)",iostat=ierr)words do while (ierr.eq.0) inblank=.true. ipos=1 do i=40,1,-1 if(words(i:i).ne.' '.and.inblank) then last=i inblank=.false. end if if(.not.inblank.and.words(i:i).eq.' ') then reversed(ipos:ipos+last-i)=words(i+1:last) ipos=ipos+last-i+1 inblank=.true. end if if(.not.inblank.and.i.eq.1) then reversed(ipos:ipos+last-1)=words(1:last) ipos=ipos+last end if end do print *,words,'=> ',reversed(1:ipos-1) read (5,fmt="(a)",iostat=ierr)words end do 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
#PowerShell
PowerShell
  $e = "This is a test Guvf vf n grfg"   [char[]](0..64+78..90+65..77+91..96+110..122+97..109+123..255)[[char[]]$e] -join ""  
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
#PicoLisp
PicoLisp
(de roman (N) (pack (make (mapc '((C D) (while (>= N D) (dec 'N D) (link C) ) ) '(M CM D CD C XC L XL X IX V IV I) (1000 900 500 400 100 90 50 40 10 9 5 4 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.
#Ruby
Ruby
def fromRoman(roman) r = roman.upcase n = 0 until r.empty? do case when r.start_with?('M') then v = 1000; len = 1 when r.start_with?('CM') then v = 900; len = 2 when r.start_with?('D') then v = 500; len = 1 when r.start_with?('CD') then v = 400; len = 2 when r.start_with?('C') then v = 100; len = 1 when r.start_with?('XC') then v = 90; len = 2 when r.start_with?('L') then v = 50; len = 1 when r.start_with?('XL') then v = 40; len = 2 when r.start_with?('X') then v = 10; len = 1 when r.start_with?('IX') then v = 9; len = 2 when r.start_with?('V') then v = 5; len = 1 when r.start_with?('IV') then v = 4; len = 2 when r.start_with?('I') then v = 1; len = 1 else raise ArgumentError.new("invalid roman numerals: " + roman) end n += v r.slice!(0,len) end n end   [ "MCMXC", "MMVIII", "MDCLXVI" ].each {|r| p r => fromRoman(r)}
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
#Bracmat
Bracmat
(repeat= string N rep .  !arg:(?string.?N) & !string:?rep & whl ' (!N+-1:>0:?N&!string !rep:?rep) & str$!rep );
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
#Brainf.2A.2A.2A
Brainf***
+++++ +++++ init first as 10 counter [-> +++++ +++++<] we add 10 to second each loopround   Now we want to loop 5 times to follow std +++++ [-> ++++ . ----- -- . +++<] print h and a each loop   and a newline because I'm kind and it looks good +++++ +++++ +++ . --- .
http://rosettacode.org/wiki/Return_multiple_values
Return multiple values
Task Show how to return more than one value from a function.
#ERRE
ERRE
  PROGRAM RETURN_VALUES   PROCEDURE SUM_DIFF(A,B->C,D) C=A+B D=A-B END PROCEDURE   BEGIN SUM_DIFF(5,3->SUM,DIFF) PRINT("Sum is";SUM) PRINT("Difference is";DIFF) END PROGRAM  
http://rosettacode.org/wiki/Return_multiple_values
Return multiple values
Task Show how to return more than one value from a function.
#Euphoria
Euphoria
include std\console.e --only for any_key, to help make running this program easy on windows GUI   integer aWholeNumber = 1 atom aFloat = 1.999999 sequence aSequence = {3, 4} sequence result = {} --empty initialized sequence   function addmultret(integer first, atom second, sequence third)--takes three kinds of input, adds them all into one element of the.. return (first + second + third[1]) + third[2] & (first * second * third[1]) * third[2] --..output sequence and multiplies them into.. end function --..the second element   result = addmultret(aWholeNumber, aFloat, aSequence) --call function, assign what it gets into result - {9.999999, 23.999988} ? result any_key()
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).
#APL
APL
∪ 1 2 3 1 2 3 4 1 1 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.
#11l
11l
F recamanSucc(seen, n, r) ‘The successor for a given Recaman term, given the set of Recaman terms seen so far.’ V back = r - n R I 0 > back | (back C seen) {n + r} E back   F recamanUntil(p) ‘All terms of the Recaman series before the first term for which the predicate p holds.’ V n = 1 V r = 0 V rs = [r] V seen = Set(rs) V blnNew = 1B L !p(seen, n, r, blnNew) r = recamanSucc(seen, n, r) blnNew = r !C seen seen.add(r) rs.append(r) n = 1 + n R rs   F enumFromTo(m) ‘Integer enumeration from m to n.’ R n -> @m .< 1 + n   print("First 15 Recaman:\n "recamanUntil((seen, n, r, _) -> n == 15)) print("First duplicated Recaman:\n "recamanUntil((seen, n, r, blnNew) -> !blnNew).last) V setK = Set(enumFromTo(0)(1000)) print("Number of Recaman terms needed to generate all integers from [0..1000]:\n "(recamanUntil((seen, n, r, blnNew) -> (blnNew & r < 1001 & :setK.is_subset(seen))).len - 1))
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.
#AutoHotkey
AutoHotkey
RemoveLines(filename, startingLine, numOfLines){ Loop, Read, %filename% if ( A_Index < StartingLine ) || ( A_Index >= StartingLine + numOfLines ) ret .= "`r`n" . A_LoopReadLine FileDelete, % FileName FileAppend, % SubStr(ret, 3), % FileName }   SetWorkingDir, % A_ScriptDir RemoveLines("test.txt", 4, 3)
http://rosettacode.org/wiki/Record_sound
Record sound
Record a monophonic 16-bit PCM sound into either memory space, a file or array. (This task neglects to specify the sample rate, and whether to use signed samples. The programs in this page might use signed 16-bit or unsigned 16-bit samples, at 8000 Hz, 44100 Hz, or any other sample rate. Therefore, these programs might not record sound in the same format.)
#Common_Lisp
Common Lisp
  (defun record (n) (with-open-file (in "/dev/dsp" :element-type '(unsigned-byte 8)) (loop repeat n collect (read-byte in)) ) ) (defun play (byte-list) (with-open-file (out "/dev/dsp" :direction :output :element-type '(unsigned-byte 8) :if-exists :append) (mapcar (lambda (b) (write-byte b out)) byte-list) ) ) (play (record 65536))  
http://rosettacode.org/wiki/Record_sound
Record sound
Record a monophonic 16-bit PCM sound into either memory space, a file or array. (This task neglects to specify the sample rate, and whether to use signed samples. The programs in this page might use signed 16-bit or unsigned 16-bit samples, at 8000 Hz, 44100 Hz, or any other sample rate. Therefore, these programs might not record sound in the same format.)
#Go
Go
package main   import ( "bufio" "fmt" "log" "os" "os/exec" "strconv" )   func check(err error) { if err != nil { log.Fatal(err) } }   func main() { scanner := bufio.NewScanner(os.Stdin) name := "" for name == "" { fmt.Print("Enter output file name (without extension) : ") scanner.Scan() name = scanner.Text() check(scanner.Err()) } name += ".wav"   rate := 0 for rate < 2000 || rate > 192000 { fmt.Print("Enter sampling rate in Hz (2000 to 192000) : ") scanner.Scan() input := scanner.Text() check(scanner.Err()) rate, _ = strconv.Atoi(input) } rateS := strconv.Itoa(rate)   dur := 0.0 for dur < 5 || dur > 30 { fmt.Print("Enter duration in seconds (5 to 30)  : ") scanner.Scan() input := scanner.Text() check(scanner.Err()) dur, _ = strconv.ParseFloat(input, 64) } durS := strconv.FormatFloat(dur, 'f', -1, 64)   fmt.Println("OK, start speaking now...") // Default arguments: -c 1, -t wav. Note only signed 16 bit format supported. args := []string{"-r", rateS, "-f", "S16_LE", "-d", durS, name} cmd := exec.Command("arecord", args...) err := cmd.Run() check(err)   fmt.Printf("'%s' created on disk and will now be played back...\n", name) cmd = exec.Command("aplay", name) err = cmd.Run() check(err) fmt.Println("Play-back completed.") }
http://rosettacode.org/wiki/Reflection/List_methods
Reflection/List methods
Task The goal is to get the methods of an object, as names, values or both. Some languages offer dynamic methods, which in general can only be inspected if a class' public API includes a way of listing them.
#Julia
Julia
methods(methods) methods(println)
http://rosettacode.org/wiki/Reflection/List_methods
Reflection/List methods
Task The goal is to get the methods of an object, as names, values or both. Some languages offer dynamic methods, which in general can only be inspected if a class' public API includes a way of listing them.
#Kotlin
Kotlin
// Version 1.2.31   import kotlin.reflect.full.functions   open class MySuperClass { fun mySuperClassMethod(){} }   open class MyClass : MySuperClass() { fun myPublicMethod(){}   internal fun myInternalMethod(){}   protected fun myProtectedMethod(){}   private fun myPrivateMethod(){} }   fun main(args: Array<String>) { val c = MyClass::class println("List of methods declared in ${c.simpleName} and its superclasses:\n") val fs = c.functions for (f in fs) println("${f.name}, ${f.visibility}") }
http://rosettacode.org/wiki/Reflection/List_properties
Reflection/List properties
Task The goal is to get the properties of an object, as names, values or both. Some languages support dynamic properties, which in general can only be inspected if a class' public API includes a way of listing them.
#ooRexx
ooRexx
/* REXX demonstrate uses of datatype() */ /* test values */ d.1='' d.2='a23' d.3='101' d.4='123' d.5='12345678901234567890' d.6='abc' d.7='aBc' d.8='1' d.9='0' d.10='Walter' d.11='ABC' d.12='f23' d.13='123' /* supported options */ t.1='A' /* Alphanumeric */ t.2='B' /* Binary */ t.3='I' /* Internal whole number */ t.4='L' /* Lowercase */ t.5='M' /* Mixed case */ t.6='N' /* Number */ t.7='O' /* lOgical */ t.8='S' /* Symbol */ t.9='U' /* Uppercase */ t.10='V' /* Variable */ t.11='W' /* Whole number */ t.12='X' /* heXadecimal */ t.13='9' /* 9 digits */   hdr=left('',20) Do j=1 To 13 hdr=hdr t.j End hdr=hdr 'datatype(v)' Say hdr Do i=1 To 13 ol=left(d.i,20) Do j=1 To 13 ol=ol datatype(d.i,t.j) End ol=ol datatype(d.i) Say ol End Say hdr
http://rosettacode.org/wiki/Reflection/List_properties
Reflection/List properties
Task The goal is to get the properties of an object, as names, values or both. Some languages support dynamic properties, which in general can only be inspected if a class' public API includes a way of listing them.
#Perl
Perl
{ package Point; use Class::Spiffy -base;   field 'x'; field 'y'; }   { package Circle; use base qw(Point); field 'r'; }   my $p1 = Point->new(x => 8, y => -5); my $c1 = Circle->new(r => 4); my $c2 = Circle->new(x => 1, y => 2, r => 3);   use Data::Dumper; say Dumper $p1; say Dumper $c1; say Dumper $c2;
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
#CLU
CLU
rep_strings = iter (s: string) yields (string) for len: int in int$from_to_by(string$size(s)/2, 1, -1) do repstr: string := string$substr(s, 1, len) attempt: string := "" while string$size(attempt) < string$size(s) do attempt := attempt || repstr end if s = string$substr(attempt, 1, string$size(s)) then yield(repstr) end end end rep_strings   start_up = proc () as = array[string] po: stream := stream$primary_output() tests: as := as$["1001110011","1110111011","0010010010","1010101010", "1111111111","0100101101","0100100","101","11","00", "1"]   for test: string in as$elements(tests) do stream$puts(po, test || ": ") for rep_str: string in rep_strings(test) do stream$puts(po, "<" || rep_str || "> ") end stream$putc(po, '\n') end end start_up
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
#Common_Lisp
Common Lisp
  (ql:quickload :alexandria) (defun rep-stringv (a-str &optional (max-rotation (floor (/ (length a-str) 2)))) ;; Exit condition if no repetition found. (cond ((< max-rotation 1) "Not a repeating string") ;; Two checks: ;; 1. Truncated string must be equal to rotation by repetion size. ;; 2. Remaining chars (rest-str) are identical to starting chars (beg-str) ((let* ((trunc (* max-rotation (truncate (length a-str) max-rotation))) (truncated-str (subseq a-str 0 trunc)) (rest-str (subseq a-str trunc)) (beg-str (subseq a-str 0 (rem (length a-str) max-rotation)))) (and (string= beg-str rest-str) (string= (alexandria:rotate (copy-seq truncated-str) max-rotation) truncated-str))) ;; If both checks pass, return the repeting string. (subseq a-str 0 max-rotation)) ;; Recurse function reducing length of rotation. (t (rep-stringv a-str (1- max-rotation)))))  
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
#D
D
void main() { import std.stdio, std.regex;   immutable s = "I am a string";   // Test. if (s.match("string$")) "Ends with 'string'.".writeln;   // Substitute. s.replace(" a ".regex, " another ").writeln; }
http://rosettacode.org/wiki/Regular_expressions
Regular expressions
Task   match a string against a regular expression   substitute part of a string using a regular expression
#Dart
Dart
RegExp regexp = new RegExp(r'\w+\!');   String capitalize(Match m) => '${m[0].substring(0, m[0].length-1).toUpperCase()}';   void main(){ String hello = 'hello hello! world world!'; String hellomodified = hello.replaceAllMapped(regexp, capitalize); print(hello); print(hellomodified); }
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
#AppleScript
AppleScript
reverseString("Hello World!")   on reverseString(str) reverse of characters of str as string end reverseString
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.
#Go
Go
package main   import "fmt"   func repeat(n int, f func()) { for i := 0; i < n; i++ { f() } }   func fn() { fmt.Println("Example") }   func main() { repeat(4, fn) }
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.
#Haskell
Haskell
import Control.Monad (replicateM_)   sampleFunction :: IO () sampleFunction = putStrLn "a"   main = replicateM_ 5 sampleFunction
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.)
#ERRE
ERRE
CMD$="REN "+OLDFILENAME$+" "+NEWFILENAME$ SHELL CMD$
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.)
#F.23
F#
open System.IO   [<EntryPoint>] let main args = File.Move("input.txt","output.txt") File.Move(@"\input.txt",@"\output.txt") Directory.Move("docs","mydocs") Directory.Move(@"\docs",@"\mydocs") 0
http://rosettacode.org/wiki/Resistor_mesh
Resistor mesh
Task Given   10×10   grid nodes   (as shown in the image)   interconnected by   1Ω   resistors as shown, find the resistance between points   A   and   B. See also   (humor, nerd sniping)   xkcd.com cartoon
#Wren
Wren
class Node { construct new(v, fixed) { _v = v _fixed = fixed }   v { _v } v=(value) { _v = value }   fixed { _fixed } fixed=(value) { _fixed = value } }   var setBoundary = Fn.new { |m| m[1][1].v = 1 m[1][1].fixed = 1 m[6][7].v = -1 m[6][7].fixed = -1 }   var calcDiff = Fn.new { |m, d, w, h| var total = 0 for (i in 0...h) { for (j in 0...w) { var v = 0 var n = 0 if (i > 0) { v = v + m[i-1][j].v n = n + 1 } if (j > 0) { v = v + m[i][j-1].v n = n + 1 } if (i + 1 < h) { v = v + m[i+1][j].v n = n + 1 } if (j + 1 < w) { v = v + m[i][j+1].v n = n + 1 } v = m[i][j].v - v/n d[i][j].v = v if (m[i][j].fixed == 0) total = total + v*v } } return total }   var iter = Fn.new { |m, w, h| var d = List.filled(h, null) for (i in 0...h) { d[i] = List.filled(w, null) for (j in 0...w) d[i][j] = Node.new(0, 0) } var cur = [0] * 3 var diff = 1e10 while (diff > 1e-24) { setBoundary.call(m) diff = calcDiff.call(m, d, w, h) for (i in 0...h) { for (j in 0...w) m[i][j].v = m[i][j].v - d[i][j].v } } for (i in 0...h) { for (j in 0...w) { var k = 0 if (i != 0) k = k + 1 if (j != 0) k = k + 1 if (i < h - 1) k = k + 1 if (j < w - 1) k = k + 1 cur[m[i][j].fixed + 1] = cur[m[i][j].fixed + 1] + d[i][j].v * k } } return (cur[2] - cur[0]) / 2 }   var S = 10 var mesh = List.filled(S, null) for (i in 0...S) { mesh[i] = List.filled(S, null) for (j in 0...S) mesh[i][j] = Node.new(0, 0) } var r = 2 / iter.call(mesh, S, S) System.print("R = %(r)")
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
#FreeBASIC
FreeBASIC
' FB 1.05.0 Win64   Sub split (s As String, sepList As String, result() As String, removeEmpty As Boolean = False) If s = "" OrElse sepList = "" Then Redim result(0) result(0) = s Return End If Dim As Integer i, j, count = 0, empty = 0, length Dim As Integer position(Len(s) + 1) position(0) = 0   For i = 0 To len(s) - 1 For j = 0 to Len(sepList) - 1 If s[i] = sepList[j] Then count += 1 position(count) = i + 1 End If Next j Next i   Redim result(count) If count = 0 Then result(0) = s Return End If   position(count + 1) = len(s) + 1   For i = 1 To count + 1 length = position(i) - position(i - 1) - 1 result(i - 1 - empty) = Mid(s, position(i - 1) + 1, length) If removeEmpty Andalso CBool(length = 0) Then empty += 1 Next   If empty > 0 Then Redim Preserve result(count - empty) End Sub   Dim s As String = "Hey you, Bub!" Dim a() As String split(s, " ", a(), true) Dim reversed As String = "" For i As Integer = UBound(a) To LBound(a) Step -1 reversed += a(i) If i > LBound(a) Then reversed += " " Next   Print "Original String = "; s Print "Reversed String = "; reversed Print Print "Press any key to quit" Sleep
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
#Prolog
Prolog
:- use_module(library(ctypes)).   runtime_entry(start) :- prompt(_, ''), rot13.   rot13 :- get0(Ch), ( is_endfile(Ch) -> true ; rot13_char(Ch, Rot), put(Rot), rot13 ).   rot13_char(Ch, Rot) :- ( is_alpha(Ch) -> to_upper(Ch, Up), Letter is Up - 0'A, Rot is Ch + ((Letter + 13) mod 26) - Letter ; Rot = Ch ).