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http://rosettacode.org/wiki/Create_an_HTML_table | Create an HTML table | Create an HTML table.
The table body should have at least three rows of three columns.
Each of these three columns should be labelled "X", "Y", and "Z".
An extra column should be added at either the extreme left or the extreme right of the table that has no heading, but is filled with sequential row numbers.
The rows of the "X", "Y", and "Z" columns should be filled with random or sequential integers having 4 digits or less.
The numbers should be aligned in the same fashion for all columns.
| #Elixir | Elixir | defmodule Table do
defp put_rows(n) do
Enum.map_join(1..n, fn i ->
"<tr align=right><th>#{i}</th>" <>
Enum.map_join(1..3, fn _ ->
"<td>#{:rand.uniform(2000)}</td>"
end) <> "</tr>\n"
end)
end
def create_table(n\\3) do
"<table border=1>\n" <>
"<th></th><th>X</th><th>Y</th><th>Z</th>\n" <>
put_rows(n) <>
"</table>"
end
end
IO.puts Table.create_table |
http://rosettacode.org/wiki/Date_format | Date format | This task has been clarified. Its programming examples are in need of review to ensure that they still fit the requirements of the task.
Task
Display the current date in the formats of:
2007-11-23 and
Friday, November 23, 2007
| #Python | Python | import datetime
today = datetime.date.today()
# The first requested format is a method of datetime objects:
today.isoformat()
# For full flexibility, use the strftime formatting codes from the link above:
today.strftime("%A, %B %d, %Y")
# This mechanism is integrated into the general string formatting system.
# You can do this with positional arguments referenced by number
"The date is {0:%A, %B %d, %Y}".format(d)
# Or keyword arguments referenced by name
"The date is {date:%A, %B %d, %Y}".format(date=d)
# Since Python 3.6, f-strings allow the value to be inserted inline
f"The date is {d:%A, %B %d, %Y}"
|
http://rosettacode.org/wiki/Date_format | Date format | This task has been clarified. Its programming examples are in need of review to ensure that they still fit the requirements of the task.
Task
Display the current date in the formats of:
2007-11-23 and
Friday, November 23, 2007
| #R | R | now <- Sys.time()
strftime(now, "%Y-%m-%d")
strftime(now, "%A, %B %d, %Y") |
http://rosettacode.org/wiki/Cramer%27s_rule | Cramer's rule | linear algebra
Cramer's rule
system of linear equations
Given
{
a
1
x
+
b
1
y
+
c
1
z
=
d
1
a
2
x
+
b
2
y
+
c
2
z
=
d
2
a
3
x
+
b
3
y
+
c
3
z
=
d
3
{\displaystyle \left\{{\begin{matrix}a_{1}x+b_{1}y+c_{1}z&={\color {red}d_{1}}\\a_{2}x+b_{2}y+c_{2}z&={\color {red}d_{2}}\\a_{3}x+b_{3}y+c_{3}z&={\color {red}d_{3}}\end{matrix}}\right.}
which in matrix format is
[
a
1
b
1
c
1
a
2
b
2
c
2
a
3
b
3
c
3
]
[
x
y
z
]
=
[
d
1
d
2
d
3
]
.
{\displaystyle {\begin{bmatrix}a_{1}&b_{1}&c_{1}\\a_{2}&b_{2}&c_{2}\\a_{3}&b_{3}&c_{3}\end{bmatrix}}{\begin{bmatrix}x\\y\\z\end{bmatrix}}={\begin{bmatrix}{\color {red}d_{1}}\\{\color {red}d_{2}}\\{\color {red}d_{3}}\end{bmatrix}}.}
Then the values of
x
,
y
{\displaystyle x,y}
and
z
{\displaystyle z}
can be found as follows:
x
=
|
d
1
b
1
c
1
d
2
b
2
c
2
d
3
b
3
c
3
|
|
a
1
b
1
c
1
a
2
b
2
c
2
a
3
b
3
c
3
|
,
y
=
|
a
1
d
1
c
1
a
2
d
2
c
2
a
3
d
3
c
3
|
|
a
1
b
1
c
1
a
2
b
2
c
2
a
3
b
3
c
3
|
,
and
z
=
|
a
1
b
1
d
1
a
2
b
2
d
2
a
3
b
3
d
3
|
|
a
1
b
1
c
1
a
2
b
2
c
2
a
3
b
3
c
3
|
.
{\displaystyle x={\frac {\begin{vmatrix}{\color {red}d_{1}}&b_{1}&c_{1}\\{\color {red}d_{2}}&b_{2}&c_{2}\\{\color {red}d_{3}}&b_{3}&c_{3}\end{vmatrix}}{\begin{vmatrix}a_{1}&b_{1}&c_{1}\\a_{2}&b_{2}&c_{2}\\a_{3}&b_{3}&c_{3}\end{vmatrix}}},\quad y={\frac {\begin{vmatrix}a_{1}&{\color {red}d_{1}}&c_{1}\\a_{2}&{\color {red}d_{2}}&c_{2}\\a_{3}&{\color {red}d_{3}}&c_{3}\end{vmatrix}}{\begin{vmatrix}a_{1}&b_{1}&c_{1}\\a_{2}&b_{2}&c_{2}\\a_{3}&b_{3}&c_{3}\end{vmatrix}}},{\text{ and }}z={\frac {\begin{vmatrix}a_{1}&b_{1}&{\color {red}d_{1}}\\a_{2}&b_{2}&{\color {red}d_{2}}\\a_{3}&b_{3}&{\color {red}d_{3}}\end{vmatrix}}{\begin{vmatrix}a_{1}&b_{1}&c_{1}\\a_{2}&b_{2}&c_{2}\\a_{3}&b_{3}&c_{3}\end{vmatrix}}}.}
Task
Given the following system of equations:
{
2
w
−
x
+
5
y
+
z
=
−
3
3
w
+
2
x
+
2
y
−
6
z
=
−
32
w
+
3
x
+
3
y
−
z
=
−
47
5
w
−
2
x
−
3
y
+
3
z
=
49
{\displaystyle {\begin{cases}2w-x+5y+z=-3\\3w+2x+2y-6z=-32\\w+3x+3y-z=-47\\5w-2x-3y+3z=49\\\end{cases}}}
solve for
w
{\displaystyle w}
,
x
{\displaystyle x}
,
y
{\displaystyle y}
and
z
{\displaystyle z}
, using Cramer's rule.
| #Prolog | Prolog | removeElement([_|Tail], 0, Tail).
removeElement([Head|Tail], J, [Head|X]) :-
J_2 is J - 1,
removeElement(Tail, J_2, X).
removeColumn([], _, []).
removeColumn([Matrix_head|Matrix_tail], J, [X|Y]) :-
removeElement(Matrix_head, J, X),
removeColumn(Matrix_tail, J, Y).
removeRow([_|Matrix_tail], 0, Matrix_tail).
removeRow([Matrix_head|Matrix_tail], I, [Matrix_head|X]) :-
I_2 is I - 1,
removeRow(Matrix_tail, I_2, X).
cofactor(Matrix, I, J, X) :-
removeRow(Matrix, I, Matrix_2),
removeColumn(Matrix_2, J, Matrix_3),
det(Matrix_3, Y),
X is (-1) ** (I + J) * Y.
det_summand(_, _, [], 0).
det_summand(Matrix, J, B, X) :-
B = [B_head|B_tail],
cofactor(Matrix, 0, J, Z),
J_2 is J + 1,
det_summand(Matrix, J_2, B_tail, Y),
X is B_head * Z + Y.
det([[X]], X).
det(Matrix, X) :-
Matrix = [Matrix_head|_],
det_summand(Matrix, 0, Matrix_head, X).
replaceElement([_|Tail], 0, New, [New|Tail]).
replaceElement([Head|Tail], J, New, [Head|Y]) :-
J_2 is J - 1,
replaceElement(Tail, J_2, New, Y).
replaceColumn([], _, _, []).
replaceColumn([Matrix_head|Matrix_tail], J, [Column_head|Column_tail], [X|Y]) :-
replaceElement(Matrix_head, J, Column_head, X),
replaceColumn(Matrix_tail, J, Column_tail, Y).
cramerElements(_, B, L, []) :- length(B, L).
cramerElements(A, B, J, [X_J|Others]) :-
replaceColumn(A, J, B, A_J),
det(A_J, Det_A_J),
det(A, Det_A),
X_J is Det_A_J / Det_A,
J_2 is J + 1,
cramerElements(A, B, J_2, Others).
cramer(A, B, X) :- cramerElements(A, B, 0, X).
results(X) :-
A = [
[2, -1, 5, 1],
[3, 2, 2, -6],
[1, 3, 3, -1],
[5, -2, -3, 3]
],
B = [-3, -32, -47, 49],
cramer(A, B, X). |
http://rosettacode.org/wiki/Create_a_file | Create a file | In this task, the job is to create a new empty file called "output.txt" of size 0 bytes
and an empty directory called "docs". This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root.
| #friendly_interactive_shell | friendly interactive shell | touch {/,}output.txt # create both /output.txt and output.txt
mkdir {/,}docs # create both /docs and docs |
http://rosettacode.org/wiki/Create_a_file | Create a file | In this task, the job is to create a new empty file called "output.txt" of size 0 bytes
and an empty directory called "docs". This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root.
| #FunL | FunL | import io.File
File( 'output.txt' ).createNewFile()
File( File.separator + 'output.txt' ).createNewFile()
File( 'docs' ).mkdir()
File( File.separator + 'docs' ).mkdir() |
http://rosettacode.org/wiki/CSV_to_HTML_translation | CSV to HTML translation | Consider a simplified CSV format where all rows are separated by a newline
and all columns are separated by commas.
No commas are allowed as field data, but the data may contain
other characters and character sequences that would
normally be escaped when converted to HTML
Task
Create a function that takes a string representation of the CSV data
and returns a text string of an HTML table representing the CSV data.
Use the following data as the CSV text to convert, and show your output.
Character,Speech
The multitude,The messiah! Show us the messiah!
Brians mother,<angry>Now you listen here! He's not the messiah; he's a very naughty boy! Now go away!</angry>
The multitude,Who are you?
Brians mother,I'm his mother; that's who!
The multitude,Behold his mother! Behold his mother!
Extra credit
Optionally allow special formatting for the first row of the table as if it is the tables header row
(via <thead> preferably; CSS if you must).
| #Groovy | Groovy | def formatCell = { cell ->
"<td>${cell.replaceAll('&','&').replaceAll('<','<')}</td>"
}
def formatRow = { row ->
"""<tr>${row.split(',').collect { cell -> formatCell(cell) }.join('')}</tr>
"""
}
def formatTable = { csv, header=false ->
def rows = csv.split('\n').collect { row -> formatRow(row) }
header \
? """
<table>
<thead>
${rows[0]}</thead>
<tbody>
${rows[1..-1].join('')}</tbody>
</table>
""" \
: """
<table>
${rows.join('')}</table>
"""
}
def formatPage = { title, csv, header=false ->
"""<html>
<head>
<title>${title}</title>
<style type="text/css">
td {background-color:#ddddff; }
thead td {background-color:#ddffdd; text-align:center; }
</style>
</head>
<body>${formatTable(csv, header)}</body>
</html>"""
} |
http://rosettacode.org/wiki/CSV_data_manipulation | CSV data manipulation | CSV spreadsheet files are suitable for storing tabular data in a relatively portable way.
The CSV format is flexible but somewhat ill-defined.
For present purposes, authors may assume that the data fields contain no commas, backslashes, or quotation marks.
Task
Read a CSV file, change some values and save the changes back to a file.
For this task we will use the following CSV file:
C1,C2,C3,C4,C5
1,5,9,13,17
2,6,10,14,18
3,7,11,15,19
4,8,12,16,20
Suggestions
Show how to add a column, headed 'SUM', of the sums of the rows.
If possible, illustrate the use of built-in or standard functions, methods, or libraries, that handle generic CSV files.
| #Perl | Perl | #!/usr/bin/perl
use warnings;
use strict;
use List::Util 'sum';
my @header = split /,/, <>;
# Remove the newline.
chomp $header[-1];
my %column_number;
for my $i (0 .. $#header) {
$column_number{$header[$i]} = $i;
}
my @rows = map [ split /,/ ], <>;
chomp $_->[-1] for @rows;
# Add 1 to the numbers in the 2nd column:
$_->[1]++ for @rows;
# Add C1 into C4:
$_->[ $column_number{C4} ] += $_->[ $column_number{C1} ] for @rows;
# Add sums to both rows and columns.
push @header, 'Sum';
$column_number{Sum} = $#header;
push @$_, sum(@$_) for @rows;
push @rows, [
map {
my $col = $_;
sum(map $_->[ $column_number{$col} ], @rows);
} @header
];
# Print the output.
print join(',' => @header), "\n";
print join(',' => @$_), "\n" for @rows;
|
http://rosettacode.org/wiki/Day_of_the_week | Day of the week | A company decides that whenever Xmas falls on a Sunday they will give their workers all extra paid holidays so that, together with any public holidays, workers will not have to work the following week (between the 25th of December and the first of January).
Task
In what years between 2008 and 2121 will the 25th of December be a Sunday?
Using any standard date handling libraries of your programming language;
compare the dates calculated with the output of other languages to discover any anomalies in the handling of dates which may be due to, for example, overflow in types used to represent dates/times similar to y2k type problems.
| #REBOL | REBOL | rebol [
Title: "Yuletide Holiday"
URL: http://rosettacode.org/wiki/Yuletide_Holiday
]
for y 2008 2121 1 [
d: to-date reduce [y 12 25]
if 7 = d/weekday [prin [y ""]]
] |
http://rosettacode.org/wiki/Day_of_the_week | Day of the week | A company decides that whenever Xmas falls on a Sunday they will give their workers all extra paid holidays so that, together with any public holidays, workers will not have to work the following week (between the 25th of December and the first of January).
Task
In what years between 2008 and 2121 will the 25th of December be a Sunday?
Using any standard date handling libraries of your programming language;
compare the dates calculated with the output of other languages to discover any anomalies in the handling of dates which may be due to, for example, overflow in types used to represent dates/times similar to y2k type problems.
| #Red | Red | Red []
repeat yy 114 [
d: to-date reduce [25 12 (2007 + yy )]
if 7 = d/weekday [ print d ] ;; 7 = sunday
]
;; or
print "version 2"
d: to-date [25 12 2008]
while [d <= 25/12/2121 ] [
if 7 = d/weekday [
print rejoin [d/day '. d/month '. d/year ]
]
d/year: d/year + 1
]
|
http://rosettacode.org/wiki/Create_a_two-dimensional_array_at_runtime | Create a two-dimensional array at runtime |
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
Get two integers from the user, then create a two-dimensional array where the two dimensions have the sizes given by those numbers, and which can be accessed in the most natural way possible. Write some element of that array, and then output that element. Finally destroy the array if not done by the language itself.
| #Java | Java | import java.util.Scanner;
public class twoDimArray {
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
int nbr1 = in.nextInt();
int nbr2 = in.nextInt();
double[][] array = new double[nbr1][nbr2];
array[0][0] = 42.0;
System.out.println("The number at place [0 0] is " + array[0][0]);
}
} |
http://rosettacode.org/wiki/Cumulative_standard_deviation | Cumulative standard deviation | Task[edit]
Write a stateful function, class, generator or co-routine that takes a series of floating point numbers, one at a time, and returns the running standard deviation of the series.
The task implementation should use the most natural programming style of those listed for the function in the implementation language; the task must state which is being used.
Do not apply Bessel's correction; the returned standard deviation should always be computed as if the sample seen so far is the entire population.
Test case
Use this to compute the standard deviation of this demonstration set,
{
2
,
4
,
4
,
4
,
5
,
5
,
7
,
9
}
{\displaystyle \{2,4,4,4,5,5,7,9\}}
, which is
2
{\displaystyle 2}
.
Related tasks
Random numbers
Tasks for calculating statistical measures
in one go
moving (sliding window)
moving (cumulative)
Mean
Arithmetic
Statistics/Basic
Averages/Arithmetic mean
Averages/Pythagorean means
Averages/Simple moving average
Geometric
Averages/Pythagorean means
Harmonic
Averages/Pythagorean means
Quadratic
Averages/Root mean square
Circular
Averages/Mean angle
Averages/Mean time of day
Median
Averages/Median
Mode
Averages/Mode
Standard deviation
Statistics/Basic
Cumulative standard deviation
| #Lobster | Lobster |
// Stats computes a running mean and variance
// See Knuth TAOCP vol 2, 3rd edition, page 232
class Stats:
M = 0.0
S = 0.0
n = 0
def incl(x):
n += 1
if n == 1:
M = x
else:
let mm = (x - M)
M += mm / n
S += mm * (x - M)
def mean(): return M
//def variance(): return (if n > 1.0: S / (n - 1.0) else: 0.0) // Bessel's correction
def variance(): return (if n > 0.0: S / n else: 0.0)
def stddev(): return sqrt(variance())
def count(): return n
def test_stdv() -> float:
let v = [2,4,4,4,5,5,7,9]
let s = Stats {}
for(v) x: s.incl(x+0.0)
print concat_string(["Mean: ", string(s.mean()), ", Std.Deviation: ", string(s.stddev())], "")
test_stdv()
|
http://rosettacode.org/wiki/CRC-32 | CRC-32 |
Task
Demonstrate a method of deriving the Cyclic Redundancy Check from within the language.
The result should be in accordance with ISO 3309, ITU-T V.42, Gzip and PNG.
Algorithms are described on Computation of CRC in Wikipedia.
This variant of CRC-32 uses LSB-first order, sets the initial CRC to FFFFFFFF16, and complements the final CRC.
For the purpose of this task, generate a CRC-32 checksum for the ASCII encoded string:
The quick brown fox jumps over the lazy dog
| #Pike | Pike | string foo = "The quick brown fox jumps over the lazy dog";
write("0x%x\n", Gz.crc32(foo)); |
http://rosettacode.org/wiki/CRC-32 | CRC-32 |
Task
Demonstrate a method of deriving the Cyclic Redundancy Check from within the language.
The result should be in accordance with ISO 3309, ITU-T V.42, Gzip and PNG.
Algorithms are described on Computation of CRC in Wikipedia.
This variant of CRC-32 uses LSB-first order, sets the initial CRC to FFFFFFFF16, and complements the final CRC.
For the purpose of this task, generate a CRC-32 checksum for the ASCII encoded string:
The quick brown fox jumps over the lazy dog
| #PL.2FI | PL/I | *process source attributes xref or(!) nest;
crct: Proc Options(main);
/*********************************************************************
* 19.08.2013 Walter Pachl derived from REXX
*********************************************************************/
Dcl (LEFT,LENGTH,RIGHT,SUBSTR,UNSPEC) Builtin;
Dcl SYSPRINT Print;
dcl tab(0:255) Bit(32);
Call mk_tab;
Call crc_32('The quick brown fox jumps over the lazy dog');
Call crc_32('Generate CRC32 Checksum For Byte Array Example');
crc_32: Proc(s);
/*********************************************************************
* compute checksum for s
*********************************************************************/
Dcl s Char(*);
Dcl d Bit(32);
Dcl d1 Bit( 8);
Dcl d2 Bit(24);
Dcl cc Char(1);
Dcl ccb Bit(8);
Dcl tib Bit(8);
Dcl ti Bin Fixed(16) Unsigned;
Dcl k Bin Fixed(16) Unsigned;
d=(32)'1'b;
Do k=1 To length(s);
d1=right(d,8);
d2=left(d,24);
cc=substr(s,k,1);
ccb=unspec(cc);
tib=d1^ccb;
Unspec(ti)=tib;
d='00000000'b!!d2^tab(ti);
End;
d=d^(32)'1'b;
Put Edit(s,'CRC_32=',b2x(d))(Skip,a(50),a,a);
Put Edit('decimal ',b2d(d))(skip,x(49),a,f(10));
End;
b2x: proc(b) Returns(char(8));
dcl b bit(32);
dcl b4 bit(4);
dcl i Bin Fixed(31);
dcl r Char(8) Var init('');
Do i=1 To 29 By 4;
b4=substr(b,i,4);
Select(b4);
When('0000'b) r=r!!'0';
When('0001'b) r=r!!'1';
When('0010'b) r=r!!'2';
When('0011'b) r=r!!'3';
When('0100'b) r=r!!'4';
When('0101'b) r=r!!'5';
When('0110'b) r=r!!'6';
When('0111'b) r=r!!'7';
When('1000'b) r=r!!'8';
When('1001'b) r=r!!'9';
When('1010'b) r=r!!'A';
When('1011'b) r=r!!'B';
When('1100'b) r=r!!'C';
When('1101'b) r=r!!'D';
When('1110'b) r=r!!'E';
When('1111'b) r=r!!'F';
End;
End;
Return(r);
End;
b2d: Proc(b) Returns(Dec Fixed(15));
Dcl b Bit(32);
Dcl r Dec Fixed(15) Init(0);
Dcl i Bin Fixed(16);
Do i=1 To 32;
r=r*2
If substr(b,i,1) Then
r=r+1;
End;
Return(r);
End;
mk_tab: Proc;
dcl b32 bit(32);
dcl lb bit( 1);
dcl ccc bit(32) Init('edb88320'bx);
dcl (i,j) Bin Fixed(15);
Do i=0 To 255;
b32=(24)'0'b!!unspec(i);
Do j=0 To 7;
lb=right(b32,1);
b32='0'b!!left(b32,31);
If lb='1'b Then
b32=b32^ccc;
End;
tab(i)=b32;
End;
End;
End; |
http://rosettacode.org/wiki/Count_the_coins | Count the coins | There are four types of common coins in US currency:
quarters (25 cents)
dimes (10 cents)
nickels (5 cents), and
pennies (1 cent)
There are six ways to make change for 15 cents:
A dime and a nickel
A dime and 5 pennies
3 nickels
2 nickels and 5 pennies
A nickel and 10 pennies
15 pennies
Task
How many ways are there to make change for a dollar using these common coins? (1 dollar = 100 cents).
Optional
Less common are dollar coins (100 cents); and very rare are half dollars (50 cents). With the addition of these two coins, how many ways are there to make change for $1000?
(Note: the answer is larger than 232).
References
an algorithm from the book Structure and Interpretation of Computer Programs.
an article in the algorithmist.
Change-making problem on Wikipedia.
| #FutureBasic | FutureBasic | include "NSLog.incl"
void local fn Doit
long penny, nickel, dime, quarter, count = 0
NSLogSetTabInterval(30)
for penny = 0 to 100
for nickel = 0 to 20
for dime = 0 to 10
for quarter = 0 to 4
if penny + nickel * 5 + dime * 10 + quarter * 25 == 100
NSLog(@"%ld pennies\t%ld nickels\t%ld dimes\t%ld quarters",penny,nickel,dime,quarter)
count++
end if
next quarter
next dime
next nickel
next penny
NSLog(@"\n%ld ways to make a dollar",count)
end fn
fn DoIt
HandleEvents |
http://rosettacode.org/wiki/Count_the_coins | Count the coins | There are four types of common coins in US currency:
quarters (25 cents)
dimes (10 cents)
nickels (5 cents), and
pennies (1 cent)
There are six ways to make change for 15 cents:
A dime and a nickel
A dime and 5 pennies
3 nickels
2 nickels and 5 pennies
A nickel and 10 pennies
15 pennies
Task
How many ways are there to make change for a dollar using these common coins? (1 dollar = 100 cents).
Optional
Less common are dollar coins (100 cents); and very rare are half dollars (50 cents). With the addition of these two coins, how many ways are there to make change for $1000?
(Note: the answer is larger than 232).
References
an algorithm from the book Structure and Interpretation of Computer Programs.
an article in the algorithmist.
Change-making problem on Wikipedia.
| #Go | Go | package main
import "fmt"
func main() {
amount := 100
fmt.Println("amount, ways to make change:", amount, countChange(amount))
}
func countChange(amount int) int64 {
return cc(amount, 4)
}
func cc(amount, kindsOfCoins int) int64 {
switch {
case amount == 0:
return 1
case amount < 0 || kindsOfCoins == 0:
return 0
}
return cc(amount, kindsOfCoins-1) +
cc(amount - firstDenomination(kindsOfCoins), kindsOfCoins)
}
func firstDenomination(kindsOfCoins int) int {
switch kindsOfCoins {
case 1:
return 1
case 2:
return 5
case 3:
return 10
case 4:
return 25
}
panic(kindsOfCoins)
} |
http://rosettacode.org/wiki/Count_occurrences_of_a_substring | Count occurrences of a substring | Task
Create a function, or show a built-in function, to count the number of non-overlapping occurrences of a substring inside a string.
The function should take two arguments:
the first argument being the string to search, and
the second a substring to be searched for.
It should return an integer count.
print countSubstring("the three truths","th")
3
// do not count substrings that overlap with previously-counted substrings:
print countSubstring("ababababab","abab")
2
The matching should yield the highest number of non-overlapping matches.
In general, this essentially means matching from left-to-right or right-to-left (see proof on talk 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
| #Elixir | Elixir | countSubstring = fn(_, "") -> 0
(str, sub) -> length(String.split(str, sub)) - 1 end
data = [ {"the three truths", "th"},
{"ababababab", "abab"},
{"abaabba*bbaba*bbab", "a*b"},
{"abaabba*bbaba*bbab", "a"},
{"abaabba*bbaba*bbab", " "},
{"abaabba*bbaba*bbab", ""},
{"", "a"},
{"", ""} ]
Enum.each(data, fn{str, sub} ->
IO.puts countSubstring.(str, sub)
end) |
http://rosettacode.org/wiki/Count_occurrences_of_a_substring | Count occurrences of a substring | Task
Create a function, or show a built-in function, to count the number of non-overlapping occurrences of a substring inside a string.
The function should take two arguments:
the first argument being the string to search, and
the second a substring to be searched for.
It should return an integer count.
print countSubstring("the three truths","th")
3
// do not count substrings that overlap with previously-counted substrings:
print countSubstring("ababababab","abab")
2
The matching should yield the highest number of non-overlapping matches.
In general, this essentially means matching from left-to-right or right-to-left (see proof on talk 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
| #Erlang | Erlang |
%% Count non-overlapping substrings in Erlang for the rosetta code wiki.
%% Implemented by J.W. Luiten
-module(substrings).
-export([main/2]).
%% String and Sub exhausted, count a match and present result
match([], [], _OrigSub, Acc) ->
Acc+1;
%% String exhausted, present result
match([], _Sub, _OrigSub, Acc) ->
Acc;
%% Sub exhausted, count a match
match(String, [], Sub, Acc) ->
match(String, Sub, Sub, Acc+1);
%% First character matches, advance
match([X|MainTail], [X|SubTail], Sub, Acc) ->
match(MainTail, SubTail, Sub, Acc);
%% First characters do not match. Keep scanning for sub in remainder of string
match([_X|MainTail], [_Y|_SubTail], Sub, Acc)->
match(MainTail, Sub, Sub, Acc).
main(String, Sub) ->
match(String, Sub, Sub, 0). |
http://rosettacode.org/wiki/Count_in_octal | Count in octal | Task
Produce a sequential count in octal, starting at zero, and using an increment of a one for each consecutive number.
Each number should appear on a single line, and the program should count until terminated, or until the maximum value of the numeric type in use is reached.
Related task
Integer sequence is a similar task without the use of octal numbers.
| #EDSAC_order_code | EDSAC order code |
[Count in octal, for Rosetta Code.
EDSAC program, Initial Orders 2.]
[Subroutine to print 17-bit non-negative integer in octal,
with suppression of leading zeros.
Input: 0F = number (not preserved)
Workspace: 0D, 4F, 5F]
T64K GK [load at location 64]
A3F T28@ [plant return link as usual]
T4D [clear whole of 4D including sandwich bit]
A2F [load 0...010 binary (permanently in 2F)]
T4F [(1) marker bit (2) flag to test for leading 0]
AF [load number]
R2F [shift 3 right]
A4D [add marker bit]
TD [store number and marker in 0D]
H29@ [mask to isolate 3-bit octal digit]
[Loop to print digits]
[10] T5F [clear acc]
C1F [top 5 bits of acc = octal digit]
U5F [to 5F for printing]
S4F [subtract flag to test for leading 0]
G18@ [skip printing if so]
O5F [print digit]
T5F [clear acc]
T4F [flag = 0, so future 0's are not skipped]
[18] T5F [clear acc]
AD [load number + marker bit, as shifted]
L2F [shift left 3 more]
TD [store back]
AF [has marker reached sign bit yet?]
E10@ [loop back if not]
[Last digit separately, in case input = 0]
T5F [clear acc]
C1F T5F O5F
[28] ZF [(planted) jump back to caller]
[29] UF [mask, 001110...0 binary]
[Main routine]
T96K GK [load at location 96]
[Constants]
[0] PD [1]
[1] #F [set figures mode]
[2] @F [carriage return]
[3] &F [line feed]
[4] K4096F [null char]
[Variable]
[5] PF [number to be printed]
[Enter with acc = 0]
[6] O1@ [set teleprinter to figures]
[7] U5@ [update number, initially 0]
TF [also to 0F for printing]
[9] A9@ G64F [call print soubroutine]
O2@ O3@ [print CR, LF]
A5@ A@ [load number, add 1]
E7@ [loop until number overflows and becomes negative]
O4@ [done; print null to flush teleprinter buffer]
ZF [halt the machine]
E6Z [define entry point]
PF [acc = 0 on entry]
[end]
|
http://rosettacode.org/wiki/Count_in_octal | Count in octal | Task
Produce a sequential count in octal, starting at zero, and using an increment of a one for each consecutive number.
Each number should appear on a single line, and the program should count until terminated, or until the maximum value of the numeric type in use is reached.
Related task
Integer sequence is a similar task without the use of octal numbers.
| #Elixir | Elixir | Stream.iterate(0,&(&1+1)) |> Enum.each(&IO.puts Integer.to_string(&1,8)) |
http://rosettacode.org/wiki/Count_in_factors | Count in factors | Task
Write a program which counts up from 1, displaying each number as the multiplication of its prime factors.
For the purpose of this task, 1 (unity) may be shown as itself.
Example
2 is prime, so it would be shown as itself.
6 is not prime; it would be shown as
2
×
3
{\displaystyle 2\times 3}
.
2144 is not prime; it would be shown as
2
×
2
×
2
×
2
×
2
×
67
{\displaystyle 2\times 2\times 2\times 2\times 2\times 67}
.
Related tasks
prime decomposition
factors of an integer
Sieve of Eratosthenes
primality by trial division
factors of a Mersenne number
trial factoring of a Mersenne number
partition an integer X into N primes
| #DWScript | DWScript | function Factorize(n : Integer) : String;
begin
if n <= 1 then
Exit('1');
var k := 2;
while n >= k do begin
while (n mod k) = 0 do begin
Result += ' * '+IntToStr(k);
n := n div k;
end;
Inc(k);
end;
Result:=SubStr(Result, 4);
end;
var i : Integer;
for i := 1 to 22 do
PrintLn(IntToStr(i) + ': ' + Factorize(i)); |
http://rosettacode.org/wiki/Create_an_HTML_table | Create an HTML table | Create an HTML table.
The table body should have at least three rows of three columns.
Each of these three columns should be labelled "X", "Y", and "Z".
An extra column should be added at either the extreme left or the extreme right of the table that has no heading, but is filled with sequential row numbers.
The rows of the "X", "Y", and "Z" columns should be filled with random or sequential integers having 4 digits or less.
The numbers should be aligned in the same fashion for all columns.
| #Erlang | Erlang |
-module( create_html_table ).
-export( [external_format/1, html_table/3, task/0] ).
external_format( XML ) -> remove_quoutes( lists:flatten(xmerl:export_simple_content([XML], xmerl_xml)) ).
html_table( Table_options, Headers, Contents ) ->
Header = html_table_header( Headers ),
Records = [html_table_record(X) || X <- Contents],
{table, Table_options, [Header | Records]}.
task() ->
Headers = [" ", "X", "Y", "Z"],
Contents = [[erlang:integer_to_list(X), random(), random(), random()] || X <- lists:seq(1, 3)],
external_format( html_table([{border, 1}, {cellpadding, 10}], Headers, Contents) ).
html_table_header( Items ) -> {tr, [], [{th, [], [X]} || X <- Items]}.
html_table_record( Items ) -> {tr, [], [{td, [], [X]} || X <- Items]}.
random() -> erlang:integer_to_list( random:uniform(1000) ).
remove_quoutes( String ) -> lists:flatten( string:tokens(String, "\"") ).
|
http://rosettacode.org/wiki/Date_format | Date format | This task has been clarified. Its programming examples are in need of review to ensure that they still fit the requirements of the task.
Task
Display the current date in the formats of:
2007-11-23 and
Friday, November 23, 2007
| #Racket | Racket | #lang racket
(require srfi/19)
;;; The first required format is an ISO-8601 year-month-day format, predefined
;;; as ~1 in date->string
(displayln (date->string (current-date) "~1"))
;;; You should be able to see how each of the components of the following format string
;;; work...
;;; ~d is zero padded day of month:
(displayln (date->string (current-date) "~A, ~B ~d, ~Y"))
;;; ~e is space padded day of month:
(displayln (date->string (current-date) "~A, ~B ~e, ~Y")) |
http://rosettacode.org/wiki/Date_format | Date format | This task has been clarified. Its programming examples are in need of review to ensure that they still fit the requirements of the task.
Task
Display the current date in the formats of:
2007-11-23 and
Friday, November 23, 2007
| #Raku | Raku | use DateTime::Format;
my $dt = DateTime.now;
say strftime('%Y-%m-%d', $dt);
say strftime('%A, %B %d, %Y', $dt); |
http://rosettacode.org/wiki/Cramer%27s_rule | Cramer's rule | linear algebra
Cramer's rule
system of linear equations
Given
{
a
1
x
+
b
1
y
+
c
1
z
=
d
1
a
2
x
+
b
2
y
+
c
2
z
=
d
2
a
3
x
+
b
3
y
+
c
3
z
=
d
3
{\displaystyle \left\{{\begin{matrix}a_{1}x+b_{1}y+c_{1}z&={\color {red}d_{1}}\\a_{2}x+b_{2}y+c_{2}z&={\color {red}d_{2}}\\a_{3}x+b_{3}y+c_{3}z&={\color {red}d_{3}}\end{matrix}}\right.}
which in matrix format is
[
a
1
b
1
c
1
a
2
b
2
c
2
a
3
b
3
c
3
]
[
x
y
z
]
=
[
d
1
d
2
d
3
]
.
{\displaystyle {\begin{bmatrix}a_{1}&b_{1}&c_{1}\\a_{2}&b_{2}&c_{2}\\a_{3}&b_{3}&c_{3}\end{bmatrix}}{\begin{bmatrix}x\\y\\z\end{bmatrix}}={\begin{bmatrix}{\color {red}d_{1}}\\{\color {red}d_{2}}\\{\color {red}d_{3}}\end{bmatrix}}.}
Then the values of
x
,
y
{\displaystyle x,y}
and
z
{\displaystyle z}
can be found as follows:
x
=
|
d
1
b
1
c
1
d
2
b
2
c
2
d
3
b
3
c
3
|
|
a
1
b
1
c
1
a
2
b
2
c
2
a
3
b
3
c
3
|
,
y
=
|
a
1
d
1
c
1
a
2
d
2
c
2
a
3
d
3
c
3
|
|
a
1
b
1
c
1
a
2
b
2
c
2
a
3
b
3
c
3
|
,
and
z
=
|
a
1
b
1
d
1
a
2
b
2
d
2
a
3
b
3
d
3
|
|
a
1
b
1
c
1
a
2
b
2
c
2
a
3
b
3
c
3
|
.
{\displaystyle x={\frac {\begin{vmatrix}{\color {red}d_{1}}&b_{1}&c_{1}\\{\color {red}d_{2}}&b_{2}&c_{2}\\{\color {red}d_{3}}&b_{3}&c_{3}\end{vmatrix}}{\begin{vmatrix}a_{1}&b_{1}&c_{1}\\a_{2}&b_{2}&c_{2}\\a_{3}&b_{3}&c_{3}\end{vmatrix}}},\quad y={\frac {\begin{vmatrix}a_{1}&{\color {red}d_{1}}&c_{1}\\a_{2}&{\color {red}d_{2}}&c_{2}\\a_{3}&{\color {red}d_{3}}&c_{3}\end{vmatrix}}{\begin{vmatrix}a_{1}&b_{1}&c_{1}\\a_{2}&b_{2}&c_{2}\\a_{3}&b_{3}&c_{3}\end{vmatrix}}},{\text{ and }}z={\frac {\begin{vmatrix}a_{1}&b_{1}&{\color {red}d_{1}}\\a_{2}&b_{2}&{\color {red}d_{2}}\\a_{3}&b_{3}&{\color {red}d_{3}}\end{vmatrix}}{\begin{vmatrix}a_{1}&b_{1}&c_{1}\\a_{2}&b_{2}&c_{2}\\a_{3}&b_{3}&c_{3}\end{vmatrix}}}.}
Task
Given the following system of equations:
{
2
w
−
x
+
5
y
+
z
=
−
3
3
w
+
2
x
+
2
y
−
6
z
=
−
32
w
+
3
x
+
3
y
−
z
=
−
47
5
w
−
2
x
−
3
y
+
3
z
=
49
{\displaystyle {\begin{cases}2w-x+5y+z=-3\\3w+2x+2y-6z=-32\\w+3x+3y-z=-47\\5w-2x-3y+3z=49\\\end{cases}}}
solve for
w
{\displaystyle w}
,
x
{\displaystyle x}
,
y
{\displaystyle y}
and
z
{\displaystyle z}
, using Cramer's rule.
| #Python | Python |
def det(m,n):
if n==1: return m[0][0]
z=0
for r in range(n):
k=m[:]
del k[r]
z+=m[r][0]*(-1)**r*det([p[1:]for p in k],n-1)
return z
w=len(t)
d=det(h,w)
if d==0:r=[]
else:r=[det([r[0:i]+[s]+r[i+1:]for r,s in zip(h,t)],w)/d for i in range(w)]
print(r)
|
http://rosettacode.org/wiki/Create_a_file | Create a file | In this task, the job is to create a new empty file called "output.txt" of size 0 bytes
and an empty directory called "docs". This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root.
| #Gambas | Gambas | Public Sub Main()
Dim byCount As Byte
Dim sToSave As String
For byCount = 0 To 50
sToSave &= Format(Str(byCount), "00") & " - Charlie was here!" & gb.NewLine
Next
File.Save(User.Home &/ "TestFile", sToSave)
Print File.Load(User.Home &/ "TestFile")
End |
http://rosettacode.org/wiki/Create_a_file | Create a file | In this task, the job is to create a new empty file called "output.txt" of size 0 bytes
and an empty directory called "docs". This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root.
| #Go | Go | package main
import (
"fmt"
"os"
)
func createFile(fn string) {
f, err := os.Create(fn)
if err != nil {
fmt.Println(err)
return
}
fmt.Println("file", fn, "created!")
f.Close()
}
func createDir(dn string) {
err := os.Mkdir(dn, 0666)
if err != nil {
fmt.Println(err)
return
}
fmt.Println("directory", dn, "created!")
}
func main() {
createFile("input.txt")
createFile("/input.txt")
createDir("docs")
createDir("/docs")
} |
http://rosettacode.org/wiki/CSV_to_HTML_translation | CSV to HTML translation | Consider a simplified CSV format where all rows are separated by a newline
and all columns are separated by commas.
No commas are allowed as field data, but the data may contain
other characters and character sequences that would
normally be escaped when converted to HTML
Task
Create a function that takes a string representation of the CSV data
and returns a text string of an HTML table representing the CSV data.
Use the following data as the CSV text to convert, and show your output.
Character,Speech
The multitude,The messiah! Show us the messiah!
Brians mother,<angry>Now you listen here! He's not the messiah; he's a very naughty boy! Now go away!</angry>
The multitude,Who are you?
Brians mother,I'm his mother; that's who!
The multitude,Behold his mother! Behold his mother!
Extra credit
Optionally allow special formatting for the first row of the table as if it is the tables header row
(via <thead> preferably; CSS if you must).
| #Haskell | Haskell | --import Data.List.Split (splitOn) -- if the import is available
splitOn :: Char -> String -> [String] -- otherwise
splitOn delim = foldr (\x rest ->
if x == delim then "" : rest
else (x:head rest):tail rest) [""]
htmlEscape :: String -> String
htmlEscape = concatMap escapeChar
where escapeChar '<' = "<"
escapeChar '>' = ">"
escapeChar '&' = "&"
escapeChar '"' = """ --"
escapeChar c = [c]
toHtmlRow :: [String] -> String
toHtmlRow [] = "<tr></tr>"
toHtmlRow cols = let htmlColumns = concatMap toHtmlCol cols
in "<tr>\n" ++ htmlColumns ++ "</tr>"
where toHtmlCol x = " <td>" ++ htmlEscape x ++ "</td>\n"
csvToTable :: String -> String
csvToTable csv = let rows = map (splitOn ',') $ lines csv
html = unlines $ map toHtmlRow rows
in "<table>\n" ++ html ++ "</table>"
main = interact csvToTable |
http://rosettacode.org/wiki/CSV_data_manipulation | CSV data manipulation | CSV spreadsheet files are suitable for storing tabular data in a relatively portable way.
The CSV format is flexible but somewhat ill-defined.
For present purposes, authors may assume that the data fields contain no commas, backslashes, or quotation marks.
Task
Read a CSV file, change some values and save the changes back to a file.
For this task we will use the following CSV file:
C1,C2,C3,C4,C5
1,5,9,13,17
2,6,10,14,18
3,7,11,15,19
4,8,12,16,20
Suggestions
Show how to add a column, headed 'SUM', of the sums of the rows.
If possible, illustrate the use of built-in or standard functions, methods, or libraries, that handle generic CSV files.
| #Phix | Phix | with javascript_semantics
constant tcsv = """
C1,C2,C3,C4,C5
1,5,9,13,17
2,6,10,14,18
3,7,11,15,19
4,8,12,16,20
"""
sequence lines = iff(platform()=JS?split(tcsv,"\n"):get_text("test.csv",GT_LF_STRIPPED))
for i=1 to length(lines) do
lines[i] = split(trim(lines[i]),',')
end for
lines[1] = join(lines[1],',')&",SUM"
for i=2 to length(lines) do
sequence s = deep_copy(lines[i]), t = {}
for j=1 to length(s) do
t &= scanf(s[j],"%d")[1][1]
end for
-- s[rand(length(s))] = rand(100) -- (if you like)
t &= sum(t)
lines[i] = sprintf("%d,%d,%d,%d,%d,%d",t)
end for
lines = join(lines,'\n')
if platform()!=JS then
integer fn = open("out.csv","w")
puts(fn,lines)
close(fn)
end if
puts(1,lines)
|
http://rosettacode.org/wiki/Day_of_the_week | Day of the week | A company decides that whenever Xmas falls on a Sunday they will give their workers all extra paid holidays so that, together with any public holidays, workers will not have to work the following week (between the 25th of December and the first of January).
Task
In what years between 2008 and 2121 will the 25th of December be a Sunday?
Using any standard date handling libraries of your programming language;
compare the dates calculated with the output of other languages to discover any anomalies in the handling of dates which may be due to, for example, overflow in types used to represent dates/times similar to y2k type problems.
| #REXX | REXX | do year=2008 to 2121
if date('w', year"1225", 's') == 'Sunday' then say year
end /*year*/ |
http://rosettacode.org/wiki/Day_of_the_week | Day of the week | A company decides that whenever Xmas falls on a Sunday they will give their workers all extra paid holidays so that, together with any public holidays, workers will not have to work the following week (between the 25th of December and the first of January).
Task
In what years between 2008 and 2121 will the 25th of December be a Sunday?
Using any standard date handling libraries of your programming language;
compare the dates calculated with the output of other languages to discover any anomalies in the handling of dates which may be due to, for example, overflow in types used to represent dates/times similar to y2k type problems.
| #Ring | Ring |
for n = 2008 to 2121
if n < 2100 leap = n - 1900 else leap = n - 1904 ok
m = (((n-1900)%7) + floor(leap/4) + 27) % 7
if m = 4 see "25 Dec " + n + nl ok
next
|
http://rosettacode.org/wiki/Create_a_two-dimensional_array_at_runtime | Create a two-dimensional array at runtime |
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
Get two integers from the user, then create a two-dimensional array where the two dimensions have the sizes given by those numbers, and which can be accessed in the most natural way possible. Write some element of that array, and then output that element. Finally destroy the array if not done by the language itself.
| #JavaScript | JavaScript | var width = Number(prompt("Enter width: "));
var height = Number(prompt("Enter height: "));
//make 2D array
var arr = new Array(height);
for (var i = 0; i < h; i++) {
arr[i] = new Array(width);
}
//set value of element
a[0][0] = 'foo';
//print value of element
console.log('arr[0][0] = ' + arr[0][0]);
//cleanup array
arr = void(0); |
http://rosettacode.org/wiki/Cumulative_standard_deviation | Cumulative standard deviation | Task[edit]
Write a stateful function, class, generator or co-routine that takes a series of floating point numbers, one at a time, and returns the running standard deviation of the series.
The task implementation should use the most natural programming style of those listed for the function in the implementation language; the task must state which is being used.
Do not apply Bessel's correction; the returned standard deviation should always be computed as if the sample seen so far is the entire population.
Test case
Use this to compute the standard deviation of this demonstration set,
{
2
,
4
,
4
,
4
,
5
,
5
,
7
,
9
}
{\displaystyle \{2,4,4,4,5,5,7,9\}}
, which is
2
{\displaystyle 2}
.
Related tasks
Random numbers
Tasks for calculating statistical measures
in one go
moving (sliding window)
moving (cumulative)
Mean
Arithmetic
Statistics/Basic
Averages/Arithmetic mean
Averages/Pythagorean means
Averages/Simple moving average
Geometric
Averages/Pythagorean means
Harmonic
Averages/Pythagorean means
Quadratic
Averages/Root mean square
Circular
Averages/Mean angle
Averages/Mean time of day
Median
Averages/Median
Mode
Averages/Mode
Standard deviation
Statistics/Basic
Cumulative standard deviation
| #Lua | Lua | function stdev()
local sum, sumsq, k = 0,0,0
return function(n)
sum, sumsq, k = sum + n, sumsq + n^2, k+1
return math.sqrt((sumsq / k) - (sum/k)^2)
end
end
ldev = stdev()
for i, v in ipairs{2,4,4,4,5,5,7,9} do
print(ldev(v))
end |
http://rosettacode.org/wiki/CRC-32 | CRC-32 |
Task
Demonstrate a method of deriving the Cyclic Redundancy Check from within the language.
The result should be in accordance with ISO 3309, ITU-T V.42, Gzip and PNG.
Algorithms are described on Computation of CRC in Wikipedia.
This variant of CRC-32 uses LSB-first order, sets the initial CRC to FFFFFFFF16, and complements the final CRC.
For the purpose of this task, generate a CRC-32 checksum for the ASCII encoded string:
The quick brown fox jumps over the lazy dog
| #PowerBASIC | PowerBASIC | #COMPILE EXE
#DIM ALL
#COMPILER PBCC 6
' ***********
FUNCTION CRC32(BYVAL p AS BYTE PTR, BYVAL NumBytes AS DWORD) AS DWORD
STATIC LUT() AS DWORD
LOCAL i, j, k, crc AS DWORD
IF ARRAYATTR(LUT(), 0) = 0 THEN
REDIM LUT(0 TO 255)
FOR i = 0 TO 255
k = i
FOR j = 0 TO 7
IF (k AND 1) THEN
SHIFT RIGHT k, 1
k XOR= &HEDB88320
ELSE
SHIFT RIGHT k, 1
END IF
NEXT j
LUT(i) = k
NEXT i
END IF
crc = &HFFFFFFFF
FOR i = 0 TO NumBytes - 1
k = (crc AND &HFF& XOR @p[i])
SHIFT RIGHT crc, 8
crc XOR= LUT(k)
NEXT i
FUNCTION = NOT crc
END FUNCTION
' ***********
FUNCTION PBMAIN () AS LONG
LOCAL s AS STRING
LOCAL crc AS DWORD
s = "The quick brown fox jumps over the lazy dog"
CON.PRINT "Text: " & s
crc = CRC32(STRPTR(s), LEN(s))
CON.PRINT "CRC32: " & HEX$(crc)
END FUNCTION |
http://rosettacode.org/wiki/CRC-32 | CRC-32 |
Task
Demonstrate a method of deriving the Cyclic Redundancy Check from within the language.
The result should be in accordance with ISO 3309, ITU-T V.42, Gzip and PNG.
Algorithms are described on Computation of CRC in Wikipedia.
This variant of CRC-32 uses LSB-first order, sets the initial CRC to FFFFFFFF16, and complements the final CRC.
For the purpose of this task, generate a CRC-32 checksum for the ASCII encoded string:
The quick brown fox jumps over the lazy dog
| #PureBasic | PureBasic |
a$="The quick brown fox jumps over the lazy dog"
UseCRC32Fingerprint() : b$=StringFingerprint(a$, #PB_Cipher_CRC32)
OpenConsole()
PrintN("CRC32 Cecksum [hex] = "+UCase(b$))
PrintN("CRC32 Cecksum [dec] = "+Val("$"+b$))
Input()
End |
http://rosettacode.org/wiki/Count_the_coins | Count the coins | There are four types of common coins in US currency:
quarters (25 cents)
dimes (10 cents)
nickels (5 cents), and
pennies (1 cent)
There are six ways to make change for 15 cents:
A dime and a nickel
A dime and 5 pennies
3 nickels
2 nickels and 5 pennies
A nickel and 10 pennies
15 pennies
Task
How many ways are there to make change for a dollar using these common coins? (1 dollar = 100 cents).
Optional
Less common are dollar coins (100 cents); and very rare are half dollars (50 cents). With the addition of these two coins, how many ways are there to make change for $1000?
(Note: the answer is larger than 232).
References
an algorithm from the book Structure and Interpretation of Computer Programs.
an article in the algorithmist.
Change-making problem on Wikipedia.
| #Groovy | Groovy | def ccR
ccR = { BigInteger tot, List<BigInteger> coins ->
BigInteger n = coins.size()
switch ([tot:tot, coins:coins]) {
case { it.tot == 0 } :
return 1g
case { it.tot < 0 || coins == [] } :
return 0g
default:
return ccR(tot, coins[1..<n]) +
ccR(tot - coins[0], coins)
}
} |
http://rosettacode.org/wiki/Count_occurrences_of_a_substring | Count occurrences of a substring | Task
Create a function, or show a built-in function, to count the number of non-overlapping occurrences of a substring inside a string.
The function should take two arguments:
the first argument being the string to search, and
the second a substring to be searched for.
It should return an integer count.
print countSubstring("the three truths","th")
3
// do not count substrings that overlap with previously-counted substrings:
print countSubstring("ababababab","abab")
2
The matching should yield the highest number of non-overlapping matches.
In general, this essentially means matching from left-to-right or right-to-left (see proof on talk 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
| #Euphoria | Euphoria | function countSubstring(sequence s, sequence sub)
integer from,count
count = 0
from = 1
while 1 do
from = match_from(sub,s,from)
if not from then
exit
end if
from += length(sub)
count += 1
end while
return count
end function
? countSubstring("the three truths","th")
? countSubstring("ababababab","abab") |
http://rosettacode.org/wiki/Count_occurrences_of_a_substring | Count occurrences of a substring | Task
Create a function, or show a built-in function, to count the number of non-overlapping occurrences of a substring inside a string.
The function should take two arguments:
the first argument being the string to search, and
the second a substring to be searched for.
It should return an integer count.
print countSubstring("the three truths","th")
3
// do not count substrings that overlap with previously-counted substrings:
print countSubstring("ababababab","abab")
2
The matching should yield the highest number of non-overlapping matches.
In general, this essentially means matching from left-to-right or right-to-left (see proof on talk 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
| #F.23 | F# | open System
let countSubstring (where :string) (what : string) =
match what with
| "" -> 0 // just a definition; infinity is not an int
| _ -> (where.Length - where.Replace(what, @"").Length) / what.Length
[<EntryPoint>]
let main argv =
let show where what =
printfn @"countSubstring(""%s"", ""%s"") = %d" where what (countSubstring where what)
show "the three truths" "th"
show "ababababab" "abab"
show "abc" ""
0 |
http://rosettacode.org/wiki/Count_in_octal | Count in octal | Task
Produce a sequential count in octal, starting at zero, and using an increment of a one for each consecutive number.
Each number should appear on a single line, and the program should count until terminated, or until the maximum value of the numeric type in use is reached.
Related task
Integer sequence is a similar task without the use of octal numbers.
| #Emacs_Lisp | Emacs Lisp | (dotimes (i most-positive-fixnum) ;; starting from 0
(message "%o" i)) |
http://rosettacode.org/wiki/Count_in_octal | Count in octal | Task
Produce a sequential count in octal, starting at zero, and using an increment of a one for each consecutive number.
Each number should appear on a single line, and the program should count until terminated, or until the maximum value of the numeric type in use is reached.
Related task
Integer sequence is a similar task without the use of octal numbers.
| #Erlang | Erlang |
F = fun(FF, I) -> io:fwrite("~.8B~n", [I]), FF(FF, I + 1) end.
|
http://rosettacode.org/wiki/Count_in_factors | Count in factors | Task
Write a program which counts up from 1, displaying each number as the multiplication of its prime factors.
For the purpose of this task, 1 (unity) may be shown as itself.
Example
2 is prime, so it would be shown as itself.
6 is not prime; it would be shown as
2
×
3
{\displaystyle 2\times 3}
.
2144 is not prime; it would be shown as
2
×
2
×
2
×
2
×
2
×
67
{\displaystyle 2\times 2\times 2\times 2\times 2\times 67}
.
Related tasks
prime decomposition
factors of an integer
Sieve of Eratosthenes
primality by trial division
factors of a Mersenne number
trial factoring of a Mersenne number
partition an integer X into N primes
| #EchoLisp | EchoLisp |
(define (task (nfrom 2) (range 20))
(for ((i (in-range nfrom (+ nfrom range))))
(writeln i "=" (string-join (prime-factors i) " x "))))
|
http://rosettacode.org/wiki/Count_in_factors | Count in factors | Task
Write a program which counts up from 1, displaying each number as the multiplication of its prime factors.
For the purpose of this task, 1 (unity) may be shown as itself.
Example
2 is prime, so it would be shown as itself.
6 is not prime; it would be shown as
2
×
3
{\displaystyle 2\times 3}
.
2144 is not prime; it would be shown as
2
×
2
×
2
×
2
×
2
×
67
{\displaystyle 2\times 2\times 2\times 2\times 2\times 67}
.
Related tasks
prime decomposition
factors of an integer
Sieve of Eratosthenes
primality by trial division
factors of a Mersenne number
trial factoring of a Mersenne number
partition an integer X into N primes
| #Eiffel | Eiffel |
class
COUNT_IN_FACTORS
feature
display_factor (p: INTEGER)
-- Factors of all integers up to 'p'.
require
p_positive: p > 0
local
factors: ARRAY [INTEGER]
do
across
1 |..| p as c
loop
io.new_line
io.put_string (c.item.out + "%T")
factors := factor (c.item)
across
factors as f
loop
io.put_integer (f.item)
if f.is_last = False then
io.put_string (" x ")
end
end
end
end
factor (p: INTEGER): ARRAY [INTEGER]
-- Prime decomposition of 'p'.
require
p_positive: p > 0
local
div, i, next, rest: INTEGER
do
create Result.make_empty
if p = 1 then
Result.force (1, 1)
end
div := 2
next := 3
rest := p
from
i := 1
until
rest = 1
loop
from
until
rest \\ div /= 0
loop
Result.force (div, i)
rest := (rest / div).floor
i := i + 1
end
div := next
next := next + 2
end
ensure
is_divisor: across Result as r all p \\ r.item = 0 end
end
end
|
http://rosettacode.org/wiki/Create_an_HTML_table | Create an HTML table | Create an HTML table.
The table body should have at least three rows of three columns.
Each of these three columns should be labelled "X", "Y", and "Z".
An extra column should be added at either the extreme left or the extreme right of the table that has no heading, but is filled with sequential row numbers.
The rows of the "X", "Y", and "Z" columns should be filled with random or sequential integers having 4 digits or less.
The numbers should be aligned in the same fashion for all columns.
| #Euphoria | Euphoria | puts(1,"<table>\n")
puts(1," <tr><th></th><th>X</th><th>Y</th><th>Z</th></tr>\n")
for i = 1 to 3 do
printf(1," <tr><td>%d</td>",i)
for j = 1 to 3 do
printf(1,"<td>%d</td>",rand(10000))
end for
puts(1,"</tr>\n")
end for
puts(1,"</table>") |
http://rosettacode.org/wiki/Date_format | Date format | This task has been clarified. Its programming examples are in need of review to ensure that they still fit the requirements of the task.
Task
Display the current date in the formats of:
2007-11-23 and
Friday, November 23, 2007
| #Raven | Raven | time int as today |
http://rosettacode.org/wiki/Date_format | Date format | This task has been clarified. Its programming examples are in need of review to ensure that they still fit the requirements of the task.
Task
Display the current date in the formats of:
2007-11-23 and
Friday, November 23, 2007
| #REBOL | REBOL | rebol [
Title: "Date Formatting"
URL: http://rosettacode.org/wiki/Date_format
]
; REBOL has no built-in pictured output.
zeropad: func [pad n][
n: to-string n
insert/dup n "0" (pad - length? n)
n
]
d02: func [n][zeropad 2 n]
print now ; Native formatting.
print rejoin [now/year "-" d02 now/month "-" d02 now/day]
print rejoin [
pick system/locale/days now/weekday ", "
pick system/locale/months now/month " "
now/day ", " now/year
] |
http://rosettacode.org/wiki/Cramer%27s_rule | Cramer's rule | linear algebra
Cramer's rule
system of linear equations
Given
{
a
1
x
+
b
1
y
+
c
1
z
=
d
1
a
2
x
+
b
2
y
+
c
2
z
=
d
2
a
3
x
+
b
3
y
+
c
3
z
=
d
3
{\displaystyle \left\{{\begin{matrix}a_{1}x+b_{1}y+c_{1}z&={\color {red}d_{1}}\\a_{2}x+b_{2}y+c_{2}z&={\color {red}d_{2}}\\a_{3}x+b_{3}y+c_{3}z&={\color {red}d_{3}}\end{matrix}}\right.}
which in matrix format is
[
a
1
b
1
c
1
a
2
b
2
c
2
a
3
b
3
c
3
]
[
x
y
z
]
=
[
d
1
d
2
d
3
]
.
{\displaystyle {\begin{bmatrix}a_{1}&b_{1}&c_{1}\\a_{2}&b_{2}&c_{2}\\a_{3}&b_{3}&c_{3}\end{bmatrix}}{\begin{bmatrix}x\\y\\z\end{bmatrix}}={\begin{bmatrix}{\color {red}d_{1}}\\{\color {red}d_{2}}\\{\color {red}d_{3}}\end{bmatrix}}.}
Then the values of
x
,
y
{\displaystyle x,y}
and
z
{\displaystyle z}
can be found as follows:
x
=
|
d
1
b
1
c
1
d
2
b
2
c
2
d
3
b
3
c
3
|
|
a
1
b
1
c
1
a
2
b
2
c
2
a
3
b
3
c
3
|
,
y
=
|
a
1
d
1
c
1
a
2
d
2
c
2
a
3
d
3
c
3
|
|
a
1
b
1
c
1
a
2
b
2
c
2
a
3
b
3
c
3
|
,
and
z
=
|
a
1
b
1
d
1
a
2
b
2
d
2
a
3
b
3
d
3
|
|
a
1
b
1
c
1
a
2
b
2
c
2
a
3
b
3
c
3
|
.
{\displaystyle x={\frac {\begin{vmatrix}{\color {red}d_{1}}&b_{1}&c_{1}\\{\color {red}d_{2}}&b_{2}&c_{2}\\{\color {red}d_{3}}&b_{3}&c_{3}\end{vmatrix}}{\begin{vmatrix}a_{1}&b_{1}&c_{1}\\a_{2}&b_{2}&c_{2}\\a_{3}&b_{3}&c_{3}\end{vmatrix}}},\quad y={\frac {\begin{vmatrix}a_{1}&{\color {red}d_{1}}&c_{1}\\a_{2}&{\color {red}d_{2}}&c_{2}\\a_{3}&{\color {red}d_{3}}&c_{3}\end{vmatrix}}{\begin{vmatrix}a_{1}&b_{1}&c_{1}\\a_{2}&b_{2}&c_{2}\\a_{3}&b_{3}&c_{3}\end{vmatrix}}},{\text{ and }}z={\frac {\begin{vmatrix}a_{1}&b_{1}&{\color {red}d_{1}}\\a_{2}&b_{2}&{\color {red}d_{2}}\\a_{3}&b_{3}&{\color {red}d_{3}}\end{vmatrix}}{\begin{vmatrix}a_{1}&b_{1}&c_{1}\\a_{2}&b_{2}&c_{2}\\a_{3}&b_{3}&c_{3}\end{vmatrix}}}.}
Task
Given the following system of equations:
{
2
w
−
x
+
5
y
+
z
=
−
3
3
w
+
2
x
+
2
y
−
6
z
=
−
32
w
+
3
x
+
3
y
−
z
=
−
47
5
w
−
2
x
−
3
y
+
3
z
=
49
{\displaystyle {\begin{cases}2w-x+5y+z=-3\\3w+2x+2y-6z=-32\\w+3x+3y-z=-47\\5w-2x-3y+3z=49\\\end{cases}}}
solve for
w
{\displaystyle w}
,
x
{\displaystyle x}
,
y
{\displaystyle y}
and
z
{\displaystyle z}
, using Cramer's rule.
| #Racket | Racket | #lang typed/racket
(require math/matrix)
(define A (matrix [[2 -1 5 1]
[3 2 2 -6]
[1 3 3 -1]
[5 -2 -3 3]]))
(define B (col-matrix [ -3
-32
-47
49]))
(matrix->vector (matrix-solve A B)) |
http://rosettacode.org/wiki/Cramer%27s_rule | Cramer's rule | linear algebra
Cramer's rule
system of linear equations
Given
{
a
1
x
+
b
1
y
+
c
1
z
=
d
1
a
2
x
+
b
2
y
+
c
2
z
=
d
2
a
3
x
+
b
3
y
+
c
3
z
=
d
3
{\displaystyle \left\{{\begin{matrix}a_{1}x+b_{1}y+c_{1}z&={\color {red}d_{1}}\\a_{2}x+b_{2}y+c_{2}z&={\color {red}d_{2}}\\a_{3}x+b_{3}y+c_{3}z&={\color {red}d_{3}}\end{matrix}}\right.}
which in matrix format is
[
a
1
b
1
c
1
a
2
b
2
c
2
a
3
b
3
c
3
]
[
x
y
z
]
=
[
d
1
d
2
d
3
]
.
{\displaystyle {\begin{bmatrix}a_{1}&b_{1}&c_{1}\\a_{2}&b_{2}&c_{2}\\a_{3}&b_{3}&c_{3}\end{bmatrix}}{\begin{bmatrix}x\\y\\z\end{bmatrix}}={\begin{bmatrix}{\color {red}d_{1}}\\{\color {red}d_{2}}\\{\color {red}d_{3}}\end{bmatrix}}.}
Then the values of
x
,
y
{\displaystyle x,y}
and
z
{\displaystyle z}
can be found as follows:
x
=
|
d
1
b
1
c
1
d
2
b
2
c
2
d
3
b
3
c
3
|
|
a
1
b
1
c
1
a
2
b
2
c
2
a
3
b
3
c
3
|
,
y
=
|
a
1
d
1
c
1
a
2
d
2
c
2
a
3
d
3
c
3
|
|
a
1
b
1
c
1
a
2
b
2
c
2
a
3
b
3
c
3
|
,
and
z
=
|
a
1
b
1
d
1
a
2
b
2
d
2
a
3
b
3
d
3
|
|
a
1
b
1
c
1
a
2
b
2
c
2
a
3
b
3
c
3
|
.
{\displaystyle x={\frac {\begin{vmatrix}{\color {red}d_{1}}&b_{1}&c_{1}\\{\color {red}d_{2}}&b_{2}&c_{2}\\{\color {red}d_{3}}&b_{3}&c_{3}\end{vmatrix}}{\begin{vmatrix}a_{1}&b_{1}&c_{1}\\a_{2}&b_{2}&c_{2}\\a_{3}&b_{3}&c_{3}\end{vmatrix}}},\quad y={\frac {\begin{vmatrix}a_{1}&{\color {red}d_{1}}&c_{1}\\a_{2}&{\color {red}d_{2}}&c_{2}\\a_{3}&{\color {red}d_{3}}&c_{3}\end{vmatrix}}{\begin{vmatrix}a_{1}&b_{1}&c_{1}\\a_{2}&b_{2}&c_{2}\\a_{3}&b_{3}&c_{3}\end{vmatrix}}},{\text{ and }}z={\frac {\begin{vmatrix}a_{1}&b_{1}&{\color {red}d_{1}}\\a_{2}&b_{2}&{\color {red}d_{2}}\\a_{3}&b_{3}&{\color {red}d_{3}}\end{vmatrix}}{\begin{vmatrix}a_{1}&b_{1}&c_{1}\\a_{2}&b_{2}&c_{2}\\a_{3}&b_{3}&c_{3}\end{vmatrix}}}.}
Task
Given the following system of equations:
{
2
w
−
x
+
5
y
+
z
=
−
3
3
w
+
2
x
+
2
y
−
6
z
=
−
32
w
+
3
x
+
3
y
−
z
=
−
47
5
w
−
2
x
−
3
y
+
3
z
=
49
{\displaystyle {\begin{cases}2w-x+5y+z=-3\\3w+2x+2y-6z=-32\\w+3x+3y-z=-47\\5w-2x-3y+3z=49\\\end{cases}}}
solve for
w
{\displaystyle w}
,
x
{\displaystyle x}
,
y
{\displaystyle y}
and
z
{\displaystyle z}
, using Cramer's rule.
| #Raku | Raku | sub det(@matrix) {
my @a = @matrix.map: { [|$_] };
my $sign = +1;
my $pivot = 1;
for ^@a -> $k {
my @r = ($k+1 .. @a.end);
my $previous-pivot = $pivot;
if 0 == ($pivot = @a[$k][$k]) {
(my $s = @r.first: { @a[$_][$k] != 0 }) // return 0;
(@a[$s],@a[$k]) = (@a[$k], @a[$s]);
my $pivot = @a[$k][$k];
$sign = -$sign;
}
for @r X @r -> ($i, $j) {
((@a[$i][$j] *= $pivot) -= @a[$i][$k]*@a[$k][$j]) /= $previous-pivot;
}
}
$sign * $pivot
}
sub cramers_rule(@A, @terms) {
gather for ^@A -> $i {
my @Ai = @A.map: { [|$_] };
for ^@terms -> $j {
@Ai[$j][$i] = @terms[$j];
}
take det(@Ai);
} »/» det(@A);
}
my @matrix = (
[2, -1, 5, 1],
[3, 2, 2, -6],
[1, 3, 3, -1],
[5, -2, -3, 3],
);
my @free_terms = (-3, -32, -47, 49);
my ($w, $x, $y, $z) = |cramers_rule(@matrix, @free_terms);
say "w = $w";
say "x = $x";
say "y = $y";
say "z = $z"; |
http://rosettacode.org/wiki/Create_a_file | Create a file | In this task, the job is to create a new empty file called "output.txt" of size 0 bytes
and an empty directory called "docs". This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root.
| #Groovy | Groovy | new File("output.txt").createNewFile()
new File(File.separator + "output.txt").createNewFile()
new File("docs").mkdir()
new File(File.separator + "docs").mkdir() |
http://rosettacode.org/wiki/Create_a_file | Create a file | In this task, the job is to create a new empty file called "output.txt" of size 0 bytes
and an empty directory called "docs". This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root.
| #Haskell | Haskell | import System.Directory
createFile name = writeFile name ""
main = do
createFile "output.txt"
createDirectory "docs"
createFile "/output.txt"
createDirectory "/docs" |
http://rosettacode.org/wiki/CSV_to_HTML_translation | CSV to HTML translation | Consider a simplified CSV format where all rows are separated by a newline
and all columns are separated by commas.
No commas are allowed as field data, but the data may contain
other characters and character sequences that would
normally be escaped when converted to HTML
Task
Create a function that takes a string representation of the CSV data
and returns a text string of an HTML table representing the CSV data.
Use the following data as the CSV text to convert, and show your output.
Character,Speech
The multitude,The messiah! Show us the messiah!
Brians mother,<angry>Now you listen here! He's not the messiah; he's a very naughty boy! Now go away!</angry>
The multitude,Who are you?
Brians mother,I'm his mother; that's who!
The multitude,Behold his mother! Behold his mother!
Extra credit
Optionally allow special formatting for the first row of the table as if it is the tables header row
(via <thead> preferably; CSS if you must).
| #Icon_and_Unicon | Icon and Unicon | procedure main(arglist)
pchar := &letters ++ &digits ++ '!?;. ' # printable chars
write("<TABLE>")
firstHead := (!arglist == "-heading")
tHead := write
while row := trim(read()) do {
if \firstHead then write(" <THEAD>") else tHead(" <TBODY>")
writes(" <TR><TD>")
while *row > 0 do
row ?:= ( (=",",writes("</TD><TD>")) |
writes( tab(many(pchar)) |
("&#" || ord(move(1))) ), tab(0))
write("</TD></TR>")
if (\firstHead) := &null then write(" </THEAD>\n <TBODY>")
tHead := 1
}
write(" </TBODY>")
write("</TABLE>")
end |
http://rosettacode.org/wiki/CSV_data_manipulation | CSV data manipulation | CSV spreadsheet files are suitable for storing tabular data in a relatively portable way.
The CSV format is flexible but somewhat ill-defined.
For present purposes, authors may assume that the data fields contain no commas, backslashes, or quotation marks.
Task
Read a CSV file, change some values and save the changes back to a file.
For this task we will use the following CSV file:
C1,C2,C3,C4,C5
1,5,9,13,17
2,6,10,14,18
3,7,11,15,19
4,8,12,16,20
Suggestions
Show how to add a column, headed 'SUM', of the sums of the rows.
If possible, illustrate the use of built-in or standard functions, methods, or libraries, that handle generic CSV files.
| #PHP | PHP |
<?php
// fputcsv() requires at least PHP 5.1.0
// file "data_in.csv" holds input data
// the result is saved in "data_out.csv"
// this version has no error-checking
$handle = fopen('data_in.csv','r');
$handle_output = fopen('data_out.csv','w');
$row = 0;
$arr = array();
while ($line = fgetcsv($handle))
{
$arr[] = $line;
}
//change some data to zeroes
$arr[1][0] = 0; // 1,5,9,13,17 => 0,5,9,13,17
$arr[2][1] = 0; // 2,6,10,14,18 => 2,0,10,14,18
//add sum and write file
foreach ($arr as $line)
{
if ($row==0)
{
array_push($line,"SUM");
}
else
{
array_push($line,array_sum($line));
}
fputcsv($handle_output, $line);
$row++;
}
?> |
http://rosettacode.org/wiki/Day_of_the_week | Day of the week | A company decides that whenever Xmas falls on a Sunday they will give their workers all extra paid holidays so that, together with any public holidays, workers will not have to work the following week (between the 25th of December and the first of January).
Task
In what years between 2008 and 2121 will the 25th of December be a Sunday?
Using any standard date handling libraries of your programming language;
compare the dates calculated with the output of other languages to discover any anomalies in the handling of dates which may be due to, for example, overflow in types used to represent dates/times similar to y2k type problems.
| #Ruby | Ruby | require 'date'
(2008..2121).each {|year| puts "25 Dec #{year}" if Date.new(year, 12, 25).sunday? } |
http://rosettacode.org/wiki/Day_of_the_week | Day of the week | A company decides that whenever Xmas falls on a Sunday they will give their workers all extra paid holidays so that, together with any public holidays, workers will not have to work the following week (between the 25th of December and the first of January).
Task
In what years between 2008 and 2121 will the 25th of December be a Sunday?
Using any standard date handling libraries of your programming language;
compare the dates calculated with the output of other languages to discover any anomalies in the handling of dates which may be due to, for example, overflow in types used to represent dates/times similar to y2k type problems.
| #Run_BASIC | Run BASIC | for year = 2008 to 2121
if val(date$("12-25-";year)) mod 7 = 5 then print "For ";year;"xmas is Sunday"
next year |
http://rosettacode.org/wiki/Create_a_two-dimensional_array_at_runtime | Create a two-dimensional array at runtime |
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
Get two integers from the user, then create a two-dimensional array where the two dimensions have the sizes given by those numbers, and which can be accessed in the most natural way possible. Write some element of that array, and then output that element. Finally destroy the array if not done by the language itself.
| #jq | jq | M | setpath([i,j]; e)
|
http://rosettacode.org/wiki/Create_a_two-dimensional_array_at_runtime | Create a two-dimensional array at runtime |
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
Get two integers from the user, then create a two-dimensional array where the two dimensions have the sizes given by those numbers, and which can be accessed in the most natural way possible. Write some element of that array, and then output that element. Finally destroy the array if not done by the language itself.
| #Julia | Julia | function input(prompt::AbstractString)
print(prompt)
return readline()
end
n = input("Upper bound for dimension 1: ") |>
x -> parse(Int, x)
m = input("Upper bound for dimension 2: ") |>
x -> parse(Int, x)
x = rand(n, m)
display(x)
x[3, 3] # overloads `getindex` generic function
x[3, 3] = 5.0 # overloads `setindex!` generic function
x::Matrix # `Matrix{T}` is an alias for `Array{T, 2}`
x = 0; gc() # Julia has no `del` command, rebind `x` and call the garbage collector |
http://rosettacode.org/wiki/Cumulative_standard_deviation | Cumulative standard deviation | Task[edit]
Write a stateful function, class, generator or co-routine that takes a series of floating point numbers, one at a time, and returns the running standard deviation of the series.
The task implementation should use the most natural programming style of those listed for the function in the implementation language; the task must state which is being used.
Do not apply Bessel's correction; the returned standard deviation should always be computed as if the sample seen so far is the entire population.
Test case
Use this to compute the standard deviation of this demonstration set,
{
2
,
4
,
4
,
4
,
5
,
5
,
7
,
9
}
{\displaystyle \{2,4,4,4,5,5,7,9\}}
, which is
2
{\displaystyle 2}
.
Related tasks
Random numbers
Tasks for calculating statistical measures
in one go
moving (sliding window)
moving (cumulative)
Mean
Arithmetic
Statistics/Basic
Averages/Arithmetic mean
Averages/Pythagorean means
Averages/Simple moving average
Geometric
Averages/Pythagorean means
Harmonic
Averages/Pythagorean means
Quadratic
Averages/Root mean square
Circular
Averages/Mean angle
Averages/Mean time of day
Median
Averages/Median
Mode
Averages/Mode
Standard deviation
Statistics/Basic
Cumulative standard deviation
| #Mathematica.2FWolfram_Language | Mathematica/Wolfram Language | runningSTDDev[n_] := (If[Not[ValueQ[$Data]], $Data = {}];StandardDeviation[AppendTo[$Data, n]]) |
http://rosettacode.org/wiki/CRC-32 | CRC-32 |
Task
Demonstrate a method of deriving the Cyclic Redundancy Check from within the language.
The result should be in accordance with ISO 3309, ITU-T V.42, Gzip and PNG.
Algorithms are described on Computation of CRC in Wikipedia.
This variant of CRC-32 uses LSB-first order, sets the initial CRC to FFFFFFFF16, and complements the final CRC.
For the purpose of this task, generate a CRC-32 checksum for the ASCII encoded string:
The quick brown fox jumps over the lazy dog
| #Python | Python | >>> s = 'The quick brown fox jumps over the lazy dog'
>>> import zlib
>>> hex(zlib.crc32(s))
'0x414fa339'
>>> import binascii
>>> hex(binascii.crc32(s))
'0x414fa339' |
http://rosettacode.org/wiki/CRC-32 | CRC-32 |
Task
Demonstrate a method of deriving the Cyclic Redundancy Check from within the language.
The result should be in accordance with ISO 3309, ITU-T V.42, Gzip and PNG.
Algorithms are described on Computation of CRC in Wikipedia.
This variant of CRC-32 uses LSB-first order, sets the initial CRC to FFFFFFFF16, and complements the final CRC.
For the purpose of this task, generate a CRC-32 checksum for the ASCII encoded string:
The quick brown fox jumps over the lazy dog
| #QB64 | QB64 |
PRINT HEX$(crc32("The quick brown fox jumps over the lazy dog"))
FUNCTION crc32~& (buf AS STRING)
STATIC table(255) AS _UNSIGNED LONG
STATIC have_table AS _BYTE
DIM crc AS _UNSIGNED LONG, k AS _UNSIGNED LONG
DIM i AS LONG, j AS LONG
IF have_table = 0 THEN
FOR i = 0 TO 255
k = i
FOR j = 0 TO 7
IF (k AND 1) THEN
k = _SHR(k, 1)
k = k XOR &HEDB88320
ELSE
k = _SHR(k, 1)
END IF
table(i) = k
NEXT
NEXT
have_table = -1
END IF
crc = NOT crc ' crc = &Hffffffff
FOR i = 1 TO LEN(buf)
crc = (_SHR(crc, 8)) XOR table((crc AND &HFF) XOR ASC(buf, i))
NEXT
crc32~& = NOT crc
END FUNCTION
|
http://rosettacode.org/wiki/Count_the_coins | Count the coins | There are four types of common coins in US currency:
quarters (25 cents)
dimes (10 cents)
nickels (5 cents), and
pennies (1 cent)
There are six ways to make change for 15 cents:
A dime and a nickel
A dime and 5 pennies
3 nickels
2 nickels and 5 pennies
A nickel and 10 pennies
15 pennies
Task
How many ways are there to make change for a dollar using these common coins? (1 dollar = 100 cents).
Optional
Less common are dollar coins (100 cents); and very rare are half dollars (50 cents). With the addition of these two coins, how many ways are there to make change for $1000?
(Note: the answer is larger than 232).
References
an algorithm from the book Structure and Interpretation of Computer Programs.
an article in the algorithmist.
Change-making problem on Wikipedia.
| #Haskell | Haskell | count :: (Integral t, Integral a) => t -> [t] -> a
count 0 _ = 1
count _ [] = 0
count x (c:coins) =
sum
[ count (x - (n * c)) coins
| n <- [0 .. (quot x c)] ]
main :: IO ()
main = print (count 100 [1, 5, 10, 25]) |
http://rosettacode.org/wiki/Count_occurrences_of_a_substring | Count occurrences of a substring | Task
Create a function, or show a built-in function, to count the number of non-overlapping occurrences of a substring inside a string.
The function should take two arguments:
the first argument being the string to search, and
the second a substring to be searched for.
It should return an integer count.
print countSubstring("the three truths","th")
3
// do not count substrings that overlap with previously-counted substrings:
print countSubstring("ababababab","abab")
2
The matching should yield the highest number of non-overlapping matches.
In general, this essentially means matching from left-to-right or right-to-left (see proof on talk 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
| #Factor | Factor | USING: math sequences splitting ;
: occurences ( seq subseq -- n ) split-subseq length 1 - ; |
http://rosettacode.org/wiki/Count_occurrences_of_a_substring | Count occurrences of a substring | Task
Create a function, or show a built-in function, to count the number of non-overlapping occurrences of a substring inside a string.
The function should take two arguments:
the first argument being the string to search, and
the second a substring to be searched for.
It should return an integer count.
print countSubstring("the three truths","th")
3
// do not count substrings that overlap with previously-counted substrings:
print countSubstring("ababababab","abab")
2
The matching should yield the highest number of non-overlapping matches.
In general, this essentially means matching from left-to-right or right-to-left (see proof on talk 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
| #Forth | Forth | : str-count ( s1 len s2 len -- n )
2swap 0 >r
begin 2over search
while 2over nip /string
r> 1+ >r
repeat 2drop 2drop r> ;
s" the three truths" s" th" str-count . \ 3
s" ababababab" s" abab" str-count . \ 2 |
http://rosettacode.org/wiki/Count_in_octal | Count in octal | Task
Produce a sequential count in octal, starting at zero, and using an increment of a one for each consecutive number.
Each number should appear on a single line, and the program should count until terminated, or until the maximum value of the numeric type in use is reached.
Related task
Integer sequence is a similar task without the use of octal numbers.
| #Euphoria | Euphoria | integer i
i = 0
while 1 do
printf(1,"%o\n",i)
i += 1
end while |
http://rosettacode.org/wiki/Count_in_octal | Count in octal | Task
Produce a sequential count in octal, starting at zero, and using an increment of a one for each consecutive number.
Each number should appear on a single line, and the program should count until terminated, or until the maximum value of the numeric type in use is reached.
Related task
Integer sequence is a similar task without the use of octal numbers.
| #F.23 | F# | let rec countInOctal num : unit =
printfn "%o" num
countInOctal (num + 1)
countInOctal 1 |
http://rosettacode.org/wiki/Count_in_factors | Count in factors | Task
Write a program which counts up from 1, displaying each number as the multiplication of its prime factors.
For the purpose of this task, 1 (unity) may be shown as itself.
Example
2 is prime, so it would be shown as itself.
6 is not prime; it would be shown as
2
×
3
{\displaystyle 2\times 3}
.
2144 is not prime; it would be shown as
2
×
2
×
2
×
2
×
2
×
67
{\displaystyle 2\times 2\times 2\times 2\times 2\times 67}
.
Related tasks
prime decomposition
factors of an integer
Sieve of Eratosthenes
primality by trial division
factors of a Mersenne number
trial factoring of a Mersenne number
partition an integer X into N primes
| #Elixir | Elixir | defmodule RC do
def factor(n), do: factor(n, 2, [])
def factor(n, i, fact) when n < i*i, do: Enum.reverse([n|fact])
def factor(n, i, fact) do
if rem(n,i)==0, do: factor(div(n,i), i, [i|fact]),
else: factor(n, i+1, fact)
end
end
Enum.each(1..20, fn n ->
IO.puts "#{n}: #{Enum.join(RC.factor(n)," x ")}" end) |
http://rosettacode.org/wiki/Count_in_factors | Count in factors | Task
Write a program which counts up from 1, displaying each number as the multiplication of its prime factors.
For the purpose of this task, 1 (unity) may be shown as itself.
Example
2 is prime, so it would be shown as itself.
6 is not prime; it would be shown as
2
×
3
{\displaystyle 2\times 3}
.
2144 is not prime; it would be shown as
2
×
2
×
2
×
2
×
2
×
67
{\displaystyle 2\times 2\times 2\times 2\times 2\times 67}
.
Related tasks
prime decomposition
factors of an integer
Sieve of Eratosthenes
primality by trial division
factors of a Mersenne number
trial factoring of a Mersenne number
partition an integer X into N primes
| #Euphoria | Euphoria | function factorize(integer n)
sequence result
integer k
if n = 1 then
return {1}
else
k = 2
result = {}
while n > 1 do
while remainder(n, k) = 0 do
result &= k
n /= k
end while
k += 1
end while
return result
end if
end function
sequence factors
for i = 1 to 22 do
printf(1, "%d: ", i)
factors = factorize(i)
for j = 1 to length(factors)-1 do
printf(1, "%d * ", factors[j])
end for
printf(1, "%d\n", factors[$])
end for |
http://rosettacode.org/wiki/Create_an_HTML_table | Create an HTML table | Create an HTML table.
The table body should have at least three rows of three columns.
Each of these three columns should be labelled "X", "Y", and "Z".
An extra column should be added at either the extreme left or the extreme right of the table that has no heading, but is filled with sequential row numbers.
The rows of the "X", "Y", and "Z" columns should be filled with random or sequential integers having 4 digits or less.
The numbers should be aligned in the same fashion for all columns.
| #F.23 | F# | open System.Xml
type XmlDocument with
member this.Add element =
this.AppendChild element
member this.Element name =
this.CreateElement(name) :> XmlNode
member this.Element (name, (attr : (string * string) list)) =
let node = this.CreateElement(name)
for a in attr do
node.SetAttribute (fst a, snd a)
node
member this.Element (name, (text : string)) =
let node = this.CreateElement(name)
node.AppendChild(this.Text text) |> ignore
node
member this.Text text =
this.CreateTextNode(text)
end
type XmlNode with
member this.Add element =
this.AppendChild element
end
let head = [""; "X"; "Y"; "Z"]
let xd = new XmlDocument()
let html = xd.Add (xd.Element("html"))
html.Add(xd.Element("head"))
.Add(xd.Element("title", "RosettaCode: Create_an_HTML_table"))
let table = html.Add(xd.Element("body")).Add(xd.Element("table", [("style", "text-align:right")]))
let tr1 = table.Add(xd.Element("tr"))
for th in head do
tr1.Add(xd.Element("th", th)) |> ignore
for i in [1; 2; 3] do
let tr = table.Add(xd.Element("tr"))
tr.Add(xd.Element("th", i.ToString())) |> ignore
for j in [1; 2; 3] do
tr.Add(xd.Element("td", ((i-1)*3+j+1000).ToString())) |> ignore
let xw = new XmlTextWriter(System.Console.Out)
xw.Formatting <- Formatting.Indented
xd.WriteContentTo(xw) |
http://rosettacode.org/wiki/Date_format | Date format | This task has been clarified. Its programming examples are in need of review to ensure that they still fit the requirements of the task.
Task
Display the current date in the formats of:
2007-11-23 and
Friday, November 23, 2007
| #RED | RED |
Red []
;; zeropad
f2n: func [d] [ if d > 9 [return d ] append copy "0" d ]
d: now/date
print rejoin [d/year "-" f2n d/month "-" f2n d/day]
print rejoin [system/locale/days/(d/weekday) ", " system/locale/months/(d/month) " " f2n d/day ", " d/year]
|
http://rosettacode.org/wiki/Date_format | Date format | This task has been clarified. Its programming examples are in need of review to ensure that they still fit the requirements of the task.
Task
Display the current date in the formats of:
2007-11-23 and
Friday, November 23, 2007
| #REXX | REXX | /*REXX pgm shows current date: yyyy-mm-dd & Dayofweek, Month dd, yyyy*/
x = date('S') /*get current date as yyyymmdd */
yyyy = left(x,4) /*pick off year (4 digs).*/
dd = right(x,2) /*pick off day-of-month (2 digs).*/
mm = substr(x,5,2) /*pick off month number (2 digs).*/
say yyyy'-'mm"-"dd /*yyyy-mm-dd with leading zeroes.*/
weekday = date('W') /*dayofweek (Monday or somesuch).*/
month = date('M') /*Month (August or somesuch).*/
zdd = dd+0 /*remove leading zero from DD */
say weekday',' month zdd"," yyyy /*format date as: Month dd, yyyy*/
/*stick a fork in it, we're done.*/ |
http://rosettacode.org/wiki/Cramer%27s_rule | Cramer's rule | linear algebra
Cramer's rule
system of linear equations
Given
{
a
1
x
+
b
1
y
+
c
1
z
=
d
1
a
2
x
+
b
2
y
+
c
2
z
=
d
2
a
3
x
+
b
3
y
+
c
3
z
=
d
3
{\displaystyle \left\{{\begin{matrix}a_{1}x+b_{1}y+c_{1}z&={\color {red}d_{1}}\\a_{2}x+b_{2}y+c_{2}z&={\color {red}d_{2}}\\a_{3}x+b_{3}y+c_{3}z&={\color {red}d_{3}}\end{matrix}}\right.}
which in matrix format is
[
a
1
b
1
c
1
a
2
b
2
c
2
a
3
b
3
c
3
]
[
x
y
z
]
=
[
d
1
d
2
d
3
]
.
{\displaystyle {\begin{bmatrix}a_{1}&b_{1}&c_{1}\\a_{2}&b_{2}&c_{2}\\a_{3}&b_{3}&c_{3}\end{bmatrix}}{\begin{bmatrix}x\\y\\z\end{bmatrix}}={\begin{bmatrix}{\color {red}d_{1}}\\{\color {red}d_{2}}\\{\color {red}d_{3}}\end{bmatrix}}.}
Then the values of
x
,
y
{\displaystyle x,y}
and
z
{\displaystyle z}
can be found as follows:
x
=
|
d
1
b
1
c
1
d
2
b
2
c
2
d
3
b
3
c
3
|
|
a
1
b
1
c
1
a
2
b
2
c
2
a
3
b
3
c
3
|
,
y
=
|
a
1
d
1
c
1
a
2
d
2
c
2
a
3
d
3
c
3
|
|
a
1
b
1
c
1
a
2
b
2
c
2
a
3
b
3
c
3
|
,
and
z
=
|
a
1
b
1
d
1
a
2
b
2
d
2
a
3
b
3
d
3
|
|
a
1
b
1
c
1
a
2
b
2
c
2
a
3
b
3
c
3
|
.
{\displaystyle x={\frac {\begin{vmatrix}{\color {red}d_{1}}&b_{1}&c_{1}\\{\color {red}d_{2}}&b_{2}&c_{2}\\{\color {red}d_{3}}&b_{3}&c_{3}\end{vmatrix}}{\begin{vmatrix}a_{1}&b_{1}&c_{1}\\a_{2}&b_{2}&c_{2}\\a_{3}&b_{3}&c_{3}\end{vmatrix}}},\quad y={\frac {\begin{vmatrix}a_{1}&{\color {red}d_{1}}&c_{1}\\a_{2}&{\color {red}d_{2}}&c_{2}\\a_{3}&{\color {red}d_{3}}&c_{3}\end{vmatrix}}{\begin{vmatrix}a_{1}&b_{1}&c_{1}\\a_{2}&b_{2}&c_{2}\\a_{3}&b_{3}&c_{3}\end{vmatrix}}},{\text{ and }}z={\frac {\begin{vmatrix}a_{1}&b_{1}&{\color {red}d_{1}}\\a_{2}&b_{2}&{\color {red}d_{2}}\\a_{3}&b_{3}&{\color {red}d_{3}}\end{vmatrix}}{\begin{vmatrix}a_{1}&b_{1}&c_{1}\\a_{2}&b_{2}&c_{2}\\a_{3}&b_{3}&c_{3}\end{vmatrix}}}.}
Task
Given the following system of equations:
{
2
w
−
x
+
5
y
+
z
=
−
3
3
w
+
2
x
+
2
y
−
6
z
=
−
32
w
+
3
x
+
3
y
−
z
=
−
47
5
w
−
2
x
−
3
y
+
3
z
=
49
{\displaystyle {\begin{cases}2w-x+5y+z=-3\\3w+2x+2y-6z=-32\\w+3x+3y-z=-47\\5w-2x-3y+3z=49\\\end{cases}}}
solve for
w
{\displaystyle w}
,
x
{\displaystyle x}
,
y
{\displaystyle y}
and
z
{\displaystyle z}
, using Cramer's rule.
| #REXX | REXX | /* REXX Use Cramer's rule to compute solutions of given linear equations */
Numeric Digits 20
names='w x y z'
M=' 2 -1 5 1',
' 3 2 2 -6',
' 1 3 3 -1',
' 5 -2 -3 3'
v=' -3',
'-32',
'-47',
' 49'
Call mk_mat(m) /* M -> a.i.j */
Do j=1 To dim /* Show the input */
ol=''
Do i=1 To dim
ol=ol format(a.i.j,6)
End
ol=ol format(word(v,j),6)
Say ol
End
Say copies('-',35)
d=det(m) /* denominator determinant */
Do k=1 To dim /* construct nominator matrix */
Do j=1 To dim
Do i=1 To dim
If i=k Then
b.i.j=word(v,j)
Else
b.i.j=a.i.j
End
End
Call show_b
d.k=det(mk_str()) /* numerator determinant */
Say word(names,k) '=' d.k/d /* compute value of variable k */
End
Exit
mk_mat: Procedure Expose a. dim /* Turn list into matrix a.i.j */
Parse Arg list
dim=sqrt(words(list))
k=0
Do j=1 To dim
Do i=1 To dim
k=k+1
a.i.j=word(list,k)
End
End
Return
mk_str: Procedure Expose b. dim /* Turn matrix b.i.j into list */
str=''
Do j=1 To dim
Do i=1 To dim
str=str b.i.j
End
End
Return str
show_b: Procedure Expose b. dim /* show numerator matrix */
do j=1 To dim
ol=''
Do i=1 To dim
ol=ol format(b.i.j,6)
end
Call dbg ol
end
Return
det: Procedure /* compute determinant */
Parse Arg list
n=words(list)
call dbg 'det:' list
do dim=1 To 10
If dim**2=n Then Leave
End
call dbg 'dim='dim
If dim=2 Then Do
det=word(list,1)*word(list,4)-word(list,2)*word(list,3)
call dbg 'det=>'det
Return det
End
k=0
Do j=1 To dim
Do i=1 To dim
k=k+1
a.i.j=word(list,k)
End
End
Do j=1 To dim
ol=j
Do i=1 To dim
ol=ol format(a.i.j,6)
End
call dbg ol
End
det=0
Do i=1 To dim
ol=''
Do j=2 To dim
Do ii=1 To dim
If ii<>i Then
ol=ol a.ii.j
End
End
call dbg 'i='i 'ol='ol
If i//2 Then
det=det+a.i.1*det(ol)
Else
det=det-a.i.1*det(ol)
End
Call dbg 'det=>>>'det
Return det
sqrt: Procedure
/* REXX ***************************************************************
* EXEC to calculate the square root of a = 2 with high precision
**********************************************************************/
Parse Arg x,prec
If prec<9 Then prec=9
prec1=2*prec
eps=10**(-prec1)
k = 1
Numeric Digits 3
r0= x
r = 1
Do i=1 By 1 Until r=r0 | (abs(r*r-x)<eps)
r0 = r
r = (r + x/r) / 2
k = min(prec1,2*k)
Numeric Digits (k + 5)
End
Numeric Digits prec
r=r+0
Return r
dbg: Return |
http://rosettacode.org/wiki/Create_a_file | Create a file | In this task, the job is to create a new empty file called "output.txt" of size 0 bytes
and an empty directory called "docs". This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root.
| #HicEst | HicEst | SYSTEM(DIR="\docs") ! create argument if not existent, make it current
OPEN(FILE="output.txt", "NEW") ! in current directory
SYSTEM(DIR="C:\docs") ! create C:\docs if not existent, make it current
OPEN(FILE="output.txt", "NEW") ! in C:\docs |
http://rosettacode.org/wiki/Create_a_file | Create a file | In this task, the job is to create a new empty file called "output.txt" of size 0 bytes
and an empty directory called "docs". This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root.
| #i | i | software {
create("output.txt")
create("docs/")
create("/output.txt")
create("/docs/")
} |
http://rosettacode.org/wiki/CSV_to_HTML_translation | CSV to HTML translation | Consider a simplified CSV format where all rows are separated by a newline
and all columns are separated by commas.
No commas are allowed as field data, but the data may contain
other characters and character sequences that would
normally be escaped when converted to HTML
Task
Create a function that takes a string representation of the CSV data
and returns a text string of an HTML table representing the CSV data.
Use the following data as the CSV text to convert, and show your output.
Character,Speech
The multitude,The messiah! Show us the messiah!
Brians mother,<angry>Now you listen here! He's not the messiah; he's a very naughty boy! Now go away!</angry>
The multitude,Who are you?
Brians mother,I'm his mother; that's who!
The multitude,Behold his mother! Behold his mother!
Extra credit
Optionally allow special formatting for the first row of the table as if it is the tables header row
(via <thead> preferably; CSS if you must).
| #J | J | require 'strings tables/csv'
encodeHTML=: ('&';'&';'<';'<';'>';'>')&stringreplace
tag=: adverb define
'starttag endtag'=.m
(,&.>/)"1 (starttag , ,&endtag) L:0 y
)
markupCells=: ('<td>';'</td>') tag
markupHdrCells=: ('<th>';'</th>') tag
markupRows=: ('<tr>';'</tr>',LF) tag
markupTable=: (('<table>',LF);'</table>') tag
makeHTMLtablefromCSV=: verb define
0 makeHTMLtablefromCSV y NB. default left arg is 0 (no header row)
:
t=. fixcsv encodeHTML y
if. x do. t=. (markupHdrCells@{. , markupCells@}.) t
else. t=. markupCells t
end.
;markupTable markupRows t
) |
http://rosettacode.org/wiki/CSV_data_manipulation | CSV data manipulation | CSV spreadsheet files are suitable for storing tabular data in a relatively portable way.
The CSV format is flexible but somewhat ill-defined.
For present purposes, authors may assume that the data fields contain no commas, backslashes, or quotation marks.
Task
Read a CSV file, change some values and save the changes back to a file.
For this task we will use the following CSV file:
C1,C2,C3,C4,C5
1,5,9,13,17
2,6,10,14,18
3,7,11,15,19
4,8,12,16,20
Suggestions
Show how to add a column, headed 'SUM', of the sums of the rows.
If possible, illustrate the use of built-in or standard functions, methods, or libraries, that handle generic CSV files.
| #PicoLisp | PicoLisp | (in "data.csv"
(prinl (line) "," "SUM")
(while (split (line) ",")
(prinl (glue "," @) "," (sum format @)) ) ) |
http://rosettacode.org/wiki/CSV_data_manipulation | CSV data manipulation | CSV spreadsheet files are suitable for storing tabular data in a relatively portable way.
The CSV format is flexible but somewhat ill-defined.
For present purposes, authors may assume that the data fields contain no commas, backslashes, or quotation marks.
Task
Read a CSV file, change some values and save the changes back to a file.
For this task we will use the following CSV file:
C1,C2,C3,C4,C5
1,5,9,13,17
2,6,10,14,18
3,7,11,15,19
4,8,12,16,20
Suggestions
Show how to add a column, headed 'SUM', of the sums of the rows.
If possible, illustrate the use of built-in or standard functions, methods, or libraries, that handle generic CSV files.
| #PL.2FI | PL/I | *process source xref attributes or(!);
csv: Proc Options(Main);
/*********************************************************************
* 19.10.2013 Walter Pachl
* 'erase d:\csv.out'
* 'set dd:in=d:\csv.in,recsize(300)'
* 'set dd:out=d:\csv.out,recsize(300)'
* Say 'Input:'
* 'type csv.in'
* 'csv'
* Say ' '
* Say 'Output:'
* 'type csv.out'
*********************************************************************/
Dcl in Record Input;
Dcl out Record Output;
On Endfile(in) Goto part2;
Dcl (INDEX,LEFT,SUBSTR,TRIM) Builtin;
Dcl (i,j,p,m,n) Bin Fixed(31) Init(0);
Dcl s Char(100) Var;
Dcl iline(10) Char(100) Var;
Dcl a(20,20) Char(10) Var;
Dcl sum Dec Fixed(3);
Dcl oline Char(100) Var;
Do i=1 By 1;
Read File(in) Into(s);
iline(i)=s;
m=i;
Call sep((s));
End;
part2:
Do i=1 To m;
If i=1 Then
oline=iline(1)!!','!!'SUM';
Else Do;
sum=0;
Do j=1 To n;
sum=sum+a(i,j);
End;
oline=iline(i)!!','!!trim(sum);
End;
Write File(out) From(oline);
End;
sep: Procedure(line);
Dcl line Char(*) Var;
loop:
Do j=1 By 1;
p=index(line,',');
If p>0 Then Do;
a(i,j)=left(line,p-1);
line=substr(line,p+1);
End;
Else Do;
a(i,j)=line;
Leave loop;
End;
End;
n=j;
End;
End; |
http://rosettacode.org/wiki/Day_of_the_week | Day of the week | A company decides that whenever Xmas falls on a Sunday they will give their workers all extra paid holidays so that, together with any public holidays, workers will not have to work the following week (between the 25th of December and the first of January).
Task
In what years between 2008 and 2121 will the 25th of December be a Sunday?
Using any standard date handling libraries of your programming language;
compare the dates calculated with the output of other languages to discover any anomalies in the handling of dates which may be due to, for example, overflow in types used to represent dates/times similar to y2k type problems.
| #Rust | Rust | extern crate chrono;
use chrono::prelude::*;
fn main() {
let years = (2008..2121).filter(|&y| Local.ymd(y, 12, 25).weekday() == Weekday::Sun).collect::<Vec<i32>>();
println!("Years = {:?}", years);
} |
http://rosettacode.org/wiki/Day_of_the_week | Day of the week | A company decides that whenever Xmas falls on a Sunday they will give their workers all extra paid holidays so that, together with any public holidays, workers will not have to work the following week (between the 25th of December and the first of January).
Task
In what years between 2008 and 2121 will the 25th of December be a Sunday?
Using any standard date handling libraries of your programming language;
compare the dates calculated with the output of other languages to discover any anomalies in the handling of dates which may be due to, for example, overflow in types used to represent dates/times similar to y2k type problems.
| #S-BASIC | S-BASIC |
$constant SUNDAY = 0
rem - compute p mod q
function mod(p, q = integer) = integer
end = p - q * (p/q)
comment
return day of week (Sun = 0, Mon = 1, etc.) for a
given Gregorian calendar date using Zeller's congruence
end
function dayofweek (mo, da, yr = integer) = integer
var y, c, z = integer
if mo < 3 then
begin
mo = mo + 10
yr = yr - 1
end
else mo = mo - 2
y = mod(yr,100)
c = int(yr / 100)
z = int((26 * mo - 2) / 10)
z = z + da + y + int(y/4) + int(c/4) - 2 * c + 777
z = mod(z,7)
end = z
rem - main program
var year = integer
print "Christmas will fall on a Sunday in"
for year=2008 to 2121
if dayofweek(12,25,year) = SUNDAY then
print year
next year
end
|
http://rosettacode.org/wiki/Create_a_two-dimensional_array_at_runtime | Create a two-dimensional array at runtime |
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
Get two integers from the user, then create a two-dimensional array where the two dimensions have the sizes given by those numbers, and which can be accessed in the most natural way possible. Write some element of that array, and then output that element. Finally destroy the array if not done by the language itself.
| #Kotlin | Kotlin | fun main(args: Array<String>) {
// build
val dim = arrayOf(10, 15)
val array = Array(dim[0], { IntArray(dim[1]) } )
// fill
array.forEachIndexed { i, it ->
it.indices.forEach { j ->
it[j] = 1 + i + j
}
}
// print
array.forEach { println(it.asList()) }
} |
http://rosettacode.org/wiki/Create_a_two-dimensional_array_at_runtime | Create a two-dimensional array at runtime |
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
Get two integers from the user, then create a two-dimensional array where the two dimensions have the sizes given by those numbers, and which can be accessed in the most natural way possible. Write some element of that array, and then output that element. Finally destroy the array if not done by the language itself.
| #Logo | Logo | make "a2 mdarray [5 5]
mdsetitem [1 1] :a2 0 ; by default, arrays are indexed starting at 1
print mditem [1 1] :a2 ; 0 |
http://rosettacode.org/wiki/Cumulative_standard_deviation | Cumulative standard deviation | Task[edit]
Write a stateful function, class, generator or co-routine that takes a series of floating point numbers, one at a time, and returns the running standard deviation of the series.
The task implementation should use the most natural programming style of those listed for the function in the implementation language; the task must state which is being used.
Do not apply Bessel's correction; the returned standard deviation should always be computed as if the sample seen so far is the entire population.
Test case
Use this to compute the standard deviation of this demonstration set,
{
2
,
4
,
4
,
4
,
5
,
5
,
7
,
9
}
{\displaystyle \{2,4,4,4,5,5,7,9\}}
, which is
2
{\displaystyle 2}
.
Related tasks
Random numbers
Tasks for calculating statistical measures
in one go
moving (sliding window)
moving (cumulative)
Mean
Arithmetic
Statistics/Basic
Averages/Arithmetic mean
Averages/Pythagorean means
Averages/Simple moving average
Geometric
Averages/Pythagorean means
Harmonic
Averages/Pythagorean means
Quadratic
Averages/Root mean square
Circular
Averages/Mean angle
Averages/Mean time of day
Median
Averages/Median
Mode
Averages/Mode
Standard deviation
Statistics/Basic
Cumulative standard deviation
| #MATLAB_.2F_Octave | MATLAB / Octave | x = [2,4,4,4,5,5,7,9];
n = length (x);
m = mean (x);
x2 = mean (x .* x);
dev= sqrt (x2 - m * m)
dev = 2 |
http://rosettacode.org/wiki/CRC-32 | CRC-32 |
Task
Demonstrate a method of deriving the Cyclic Redundancy Check from within the language.
The result should be in accordance with ISO 3309, ITU-T V.42, Gzip and PNG.
Algorithms are described on Computation of CRC in Wikipedia.
This variant of CRC-32 uses LSB-first order, sets the initial CRC to FFFFFFFF16, and complements the final CRC.
For the purpose of this task, generate a CRC-32 checksum for the ASCII encoded string:
The quick brown fox jumps over the lazy dog
| #Quackery | Quackery | [ table ] is crctable ( n --> n )
256 times
[ i^ 8 times
[ dup 1 >>
swap 1 & if
[ hex EDB88320 ^ ] ]
' crctable put ]
[ hex FFFFFFFF swap
witheach
[ over ^ hex FF &
crctable
swap 8 >> ^ ]
hex FFFFFFFF ^ ] is crc-32 ( [ --> n )
$ "The quick brown fox jumps over the lazy dog" crc-32
16 base put
echo
base release |
http://rosettacode.org/wiki/CRC-32 | CRC-32 |
Task
Demonstrate a method of deriving the Cyclic Redundancy Check from within the language.
The result should be in accordance with ISO 3309, ITU-T V.42, Gzip and PNG.
Algorithms are described on Computation of CRC in Wikipedia.
This variant of CRC-32 uses LSB-first order, sets the initial CRC to FFFFFFFF16, and complements the final CRC.
For the purpose of this task, generate a CRC-32 checksum for the ASCII encoded string:
The quick brown fox jumps over the lazy dog
| #R | R |
digest("The quick brown fox jumps over the lazy dog","crc32", serialize=F)
|
http://rosettacode.org/wiki/Count_the_coins | Count the coins | There are four types of common coins in US currency:
quarters (25 cents)
dimes (10 cents)
nickels (5 cents), and
pennies (1 cent)
There are six ways to make change for 15 cents:
A dime and a nickel
A dime and 5 pennies
3 nickels
2 nickels and 5 pennies
A nickel and 10 pennies
15 pennies
Task
How many ways are there to make change for a dollar using these common coins? (1 dollar = 100 cents).
Optional
Less common are dollar coins (100 cents); and very rare are half dollars (50 cents). With the addition of these two coins, how many ways are there to make change for $1000?
(Note: the answer is larger than 232).
References
an algorithm from the book Structure and Interpretation of Computer Programs.
an article in the algorithmist.
Change-making problem on Wikipedia.
| #Icon_and_Unicon | Icon and Unicon | procedure main()
US_coins := [1, 5, 10, 25]
US_allcoins := [1,5,10,25,50,100]
EU_coins := [1, 2, 5, 10, 20, 50, 100, 200]
CDN_coins := [1,5,10,25,100,200]
CDN_allcoins := [1,5,10,25,50,100,200]
every trans := ![ [15,US_coins],
[100,US_coins],
[1000*100,US_allcoins]
] do
printf("There are %i ways to count change for %i using %s coins.\n",CountCoins!trans,trans[1],ShowList(trans[2]))
end
procedure ShowList(L) # helper list to string
every (s := "[ ") ||:= !L || " "
return s || "]"
end |
http://rosettacode.org/wiki/Count_occurrences_of_a_substring | Count occurrences of a substring | Task
Create a function, or show a built-in function, to count the number of non-overlapping occurrences of a substring inside a string.
The function should take two arguments:
the first argument being the string to search, and
the second a substring to be searched for.
It should return an integer count.
print countSubstring("the three truths","th")
3
// do not count substrings that overlap with previously-counted substrings:
print countSubstring("ababababab","abab")
2
The matching should yield the highest number of non-overlapping matches.
In general, this essentially means matching from left-to-right or right-to-left (see proof on talk 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
| #Fortran | Fortran | program Example
implicit none
integer :: n
n = countsubstring("the three truths", "th")
write(*,*) n
n = countsubstring("ababababab", "abab")
write(*,*) n
n = countsubstring("abaabba*bbaba*bbab", "a*b")
write(*,*) n
contains
function countsubstring(s1, s2) result(c)
character(*), intent(in) :: s1, s2
integer :: c, p, posn
c = 0
if(len(s2) == 0) return
p = 1
do
posn = index(s1(p:), s2)
if(posn == 0) return
c = c + 1
p = p + posn + len(s2) - 1
end do
end function
end program |
http://rosettacode.org/wiki/Count_in_octal | Count in octal | Task
Produce a sequential count in octal, starting at zero, and using an increment of a one for each consecutive number.
Each number should appear on a single line, and the program should count until terminated, or until the maximum value of the numeric type in use is reached.
Related task
Integer sequence is a similar task without the use of octal numbers.
| #Factor | Factor | USING: kernel math prettyprint ;
0 [ dup .o 1 + t ] loop |
http://rosettacode.org/wiki/Count_in_octal | Count in octal | Task
Produce a sequential count in octal, starting at zero, and using an increment of a one for each consecutive number.
Each number should appear on a single line, and the program should count until terminated, or until the maximum value of the numeric type in use is reached.
Related task
Integer sequence is a similar task without the use of octal numbers.
| #Forth | Forth | : octal ( -- ) 8 base ! ; \ where unavailable
octal ints |
http://rosettacode.org/wiki/Count_in_factors | Count in factors | Task
Write a program which counts up from 1, displaying each number as the multiplication of its prime factors.
For the purpose of this task, 1 (unity) may be shown as itself.
Example
2 is prime, so it would be shown as itself.
6 is not prime; it would be shown as
2
×
3
{\displaystyle 2\times 3}
.
2144 is not prime; it would be shown as
2
×
2
×
2
×
2
×
2
×
67
{\displaystyle 2\times 2\times 2\times 2\times 2\times 67}
.
Related tasks
prime decomposition
factors of an integer
Sieve of Eratosthenes
primality by trial division
factors of a Mersenne number
trial factoring of a Mersenne number
partition an integer X into N primes
| #F.23 | F# | let factorsOf (num) =
Seq.unfold (fun (f, n) ->
let rec genFactor (f, n) =
if f > n then None
elif n % f = 0 then Some (f, (f, n/f))
else genFactor (f+1, n)
genFactor (f, n)) (2, num)
let showLines = Seq.concat (seq { yield seq{ yield(Seq.singleton 1)}; yield (Seq.skip 2 (Seq.initInfinite factorsOf))})
showLines |> Seq.iteri (fun i f -> printfn "%d = %s" (i+1) (String.Join(" * ", Seq.toArray f))) |
http://rosettacode.org/wiki/Create_an_HTML_table | Create an HTML table | Create an HTML table.
The table body should have at least three rows of three columns.
Each of these three columns should be labelled "X", "Y", and "Z".
An extra column should be added at either the extreme left or the extreme right of the table that has no heading, but is filled with sequential row numbers.
The rows of the "X", "Y", and "Z" columns should be filled with random or sequential integers having 4 digits or less.
The numbers should be aligned in the same fashion for all columns.
| #Factor | Factor | USING: html.streams literals prettyprint random xml.writer ;
: rnd ( -- n ) 10,000 random ;
{
{ "" "X" "Y" "Z" }
${ 1 rnd rnd rnd }
${ 2 rnd rnd rnd }
${ 3 rnd rnd rnd }
}
[ simple-table. ] with-html-writer pprint-xml |
http://rosettacode.org/wiki/Date_format | Date format | This task has been clarified. Its programming examples are in need of review to ensure that they still fit the requirements of the task.
Task
Display the current date in the formats of:
2007-11-23 and
Friday, November 23, 2007
| #Ring | Ring |
dateStr = date()
date1 = timelist()[19] + "-" + timelist()[10] + "-" + timelist()[6]
date2 = timelist()[2] + ", " + timelist()[4] + " " + timelist()[6] + ", " + timelist()[19] + nl
? dateStr
? date1
? date2
/*
timelist() ---> List contains the time and date information.
Index Value
----------------------------
1 - abbreviated weekday name
2 - full weekday name
3 - abbreviated month name
4 - full month name
5 - Date & Time
6 - Day of the month
7 - Hour (24)
8 - Hour (12)
9 - Day of the year
10 - Month of the year
11 - Minutes after hour
12 - AM or PM
13 - Seconds after the hour
14 - Week of the year (sun-sat)
15 - day of the week
16 - date
17 - time
18 - year of the century
19 - year
20 - time zone
21 - percent sign
*/
|
http://rosettacode.org/wiki/Date_format | Date format | This task has been clarified. Its programming examples are in need of review to ensure that they still fit the requirements of the task.
Task
Display the current date in the formats of:
2007-11-23 and
Friday, November 23, 2007
| #Ruby | Ruby | puts Time.now
puts Time.now.strftime('%Y-%m-%d')
puts Time.now.strftime('%F') # same as %Y-%m-%d (ISO 8601 date formats)
puts Time.now.strftime('%A, %B %d, %Y') |
http://rosettacode.org/wiki/Cramer%27s_rule | Cramer's rule | linear algebra
Cramer's rule
system of linear equations
Given
{
a
1
x
+
b
1
y
+
c
1
z
=
d
1
a
2
x
+
b
2
y
+
c
2
z
=
d
2
a
3
x
+
b
3
y
+
c
3
z
=
d
3
{\displaystyle \left\{{\begin{matrix}a_{1}x+b_{1}y+c_{1}z&={\color {red}d_{1}}\\a_{2}x+b_{2}y+c_{2}z&={\color {red}d_{2}}\\a_{3}x+b_{3}y+c_{3}z&={\color {red}d_{3}}\end{matrix}}\right.}
which in matrix format is
[
a
1
b
1
c
1
a
2
b
2
c
2
a
3
b
3
c
3
]
[
x
y
z
]
=
[
d
1
d
2
d
3
]
.
{\displaystyle {\begin{bmatrix}a_{1}&b_{1}&c_{1}\\a_{2}&b_{2}&c_{2}\\a_{3}&b_{3}&c_{3}\end{bmatrix}}{\begin{bmatrix}x\\y\\z\end{bmatrix}}={\begin{bmatrix}{\color {red}d_{1}}\\{\color {red}d_{2}}\\{\color {red}d_{3}}\end{bmatrix}}.}
Then the values of
x
,
y
{\displaystyle x,y}
and
z
{\displaystyle z}
can be found as follows:
x
=
|
d
1
b
1
c
1
d
2
b
2
c
2
d
3
b
3
c
3
|
|
a
1
b
1
c
1
a
2
b
2
c
2
a
3
b
3
c
3
|
,
y
=
|
a
1
d
1
c
1
a
2
d
2
c
2
a
3
d
3
c
3
|
|
a
1
b
1
c
1
a
2
b
2
c
2
a
3
b
3
c
3
|
,
and
z
=
|
a
1
b
1
d
1
a
2
b
2
d
2
a
3
b
3
d
3
|
|
a
1
b
1
c
1
a
2
b
2
c
2
a
3
b
3
c
3
|
.
{\displaystyle x={\frac {\begin{vmatrix}{\color {red}d_{1}}&b_{1}&c_{1}\\{\color {red}d_{2}}&b_{2}&c_{2}\\{\color {red}d_{3}}&b_{3}&c_{3}\end{vmatrix}}{\begin{vmatrix}a_{1}&b_{1}&c_{1}\\a_{2}&b_{2}&c_{2}\\a_{3}&b_{3}&c_{3}\end{vmatrix}}},\quad y={\frac {\begin{vmatrix}a_{1}&{\color {red}d_{1}}&c_{1}\\a_{2}&{\color {red}d_{2}}&c_{2}\\a_{3}&{\color {red}d_{3}}&c_{3}\end{vmatrix}}{\begin{vmatrix}a_{1}&b_{1}&c_{1}\\a_{2}&b_{2}&c_{2}\\a_{3}&b_{3}&c_{3}\end{vmatrix}}},{\text{ and }}z={\frac {\begin{vmatrix}a_{1}&b_{1}&{\color {red}d_{1}}\\a_{2}&b_{2}&{\color {red}d_{2}}\\a_{3}&b_{3}&{\color {red}d_{3}}\end{vmatrix}}{\begin{vmatrix}a_{1}&b_{1}&c_{1}\\a_{2}&b_{2}&c_{2}\\a_{3}&b_{3}&c_{3}\end{vmatrix}}}.}
Task
Given the following system of equations:
{
2
w
−
x
+
5
y
+
z
=
−
3
3
w
+
2
x
+
2
y
−
6
z
=
−
32
w
+
3
x
+
3
y
−
z
=
−
47
5
w
−
2
x
−
3
y
+
3
z
=
49
{\displaystyle {\begin{cases}2w-x+5y+z=-3\\3w+2x+2y-6z=-32\\w+3x+3y-z=-47\\5w-2x-3y+3z=49\\\end{cases}}}
solve for
w
{\displaystyle w}
,
x
{\displaystyle x}
,
y
{\displaystyle y}
and
z
{\displaystyle z}
, using Cramer's rule.
| #Ruby | Ruby | require 'matrix'
def cramers_rule(a, terms)
raise ArgumentError, " Matrix not square" unless a.square?
cols = a.to_a.transpose
cols.each_index.map do |i|
c = cols.dup
c[i] = terms
Matrix.columns(c).det / a.det
end
end
matrix = Matrix[
[2, -1, 5, 1],
[3, 2, 2, -6],
[1, 3, 3, -1],
[5, -2, -3, 3],
]
vector = [-3, -32, -47, 49]
puts cramers_rule(matrix, vector) |
http://rosettacode.org/wiki/Cramer%27s_rule | Cramer's rule | linear algebra
Cramer's rule
system of linear equations
Given
{
a
1
x
+
b
1
y
+
c
1
z
=
d
1
a
2
x
+
b
2
y
+
c
2
z
=
d
2
a
3
x
+
b
3
y
+
c
3
z
=
d
3
{\displaystyle \left\{{\begin{matrix}a_{1}x+b_{1}y+c_{1}z&={\color {red}d_{1}}\\a_{2}x+b_{2}y+c_{2}z&={\color {red}d_{2}}\\a_{3}x+b_{3}y+c_{3}z&={\color {red}d_{3}}\end{matrix}}\right.}
which in matrix format is
[
a
1
b
1
c
1
a
2
b
2
c
2
a
3
b
3
c
3
]
[
x
y
z
]
=
[
d
1
d
2
d
3
]
.
{\displaystyle {\begin{bmatrix}a_{1}&b_{1}&c_{1}\\a_{2}&b_{2}&c_{2}\\a_{3}&b_{3}&c_{3}\end{bmatrix}}{\begin{bmatrix}x\\y\\z\end{bmatrix}}={\begin{bmatrix}{\color {red}d_{1}}\\{\color {red}d_{2}}\\{\color {red}d_{3}}\end{bmatrix}}.}
Then the values of
x
,
y
{\displaystyle x,y}
and
z
{\displaystyle z}
can be found as follows:
x
=
|
d
1
b
1
c
1
d
2
b
2
c
2
d
3
b
3
c
3
|
|
a
1
b
1
c
1
a
2
b
2
c
2
a
3
b
3
c
3
|
,
y
=
|
a
1
d
1
c
1
a
2
d
2
c
2
a
3
d
3
c
3
|
|
a
1
b
1
c
1
a
2
b
2
c
2
a
3
b
3
c
3
|
,
and
z
=
|
a
1
b
1
d
1
a
2
b
2
d
2
a
3
b
3
d
3
|
|
a
1
b
1
c
1
a
2
b
2
c
2
a
3
b
3
c
3
|
.
{\displaystyle x={\frac {\begin{vmatrix}{\color {red}d_{1}}&b_{1}&c_{1}\\{\color {red}d_{2}}&b_{2}&c_{2}\\{\color {red}d_{3}}&b_{3}&c_{3}\end{vmatrix}}{\begin{vmatrix}a_{1}&b_{1}&c_{1}\\a_{2}&b_{2}&c_{2}\\a_{3}&b_{3}&c_{3}\end{vmatrix}}},\quad y={\frac {\begin{vmatrix}a_{1}&{\color {red}d_{1}}&c_{1}\\a_{2}&{\color {red}d_{2}}&c_{2}\\a_{3}&{\color {red}d_{3}}&c_{3}\end{vmatrix}}{\begin{vmatrix}a_{1}&b_{1}&c_{1}\\a_{2}&b_{2}&c_{2}\\a_{3}&b_{3}&c_{3}\end{vmatrix}}},{\text{ and }}z={\frac {\begin{vmatrix}a_{1}&b_{1}&{\color {red}d_{1}}\\a_{2}&b_{2}&{\color {red}d_{2}}\\a_{3}&b_{3}&{\color {red}d_{3}}\end{vmatrix}}{\begin{vmatrix}a_{1}&b_{1}&c_{1}\\a_{2}&b_{2}&c_{2}\\a_{3}&b_{3}&c_{3}\end{vmatrix}}}.}
Task
Given the following system of equations:
{
2
w
−
x
+
5
y
+
z
=
−
3
3
w
+
2
x
+
2
y
−
6
z
=
−
32
w
+
3
x
+
3
y
−
z
=
−
47
5
w
−
2
x
−
3
y
+
3
z
=
49
{\displaystyle {\begin{cases}2w-x+5y+z=-3\\3w+2x+2y-6z=-32\\w+3x+3y-z=-47\\5w-2x-3y+3z=49\\\end{cases}}}
solve for
w
{\displaystyle w}
,
x
{\displaystyle x}
,
y
{\displaystyle y}
and
z
{\displaystyle z}
, using Cramer's rule.
| #Rust | Rust | use std::ops::{Index, IndexMut};
fn main() {
let m = matrix(
vec![
2., -1., 5., 1., 3., 2., 2., -6., 1., 3., 3., -1., 5., -2., -3., 3.,
],
4,
);
let mm = m.solve(&vec![-3., -32., -47., 49.]);
println!("{:?}", mm);
}
#[derive(Clone)]
struct Matrix {
elts: Vec<f64>,
dim: usize,
}
impl Matrix {
// Compute determinant using cofactor method
// Using Gaussian elimination would have been more efficient, but it also solves the linear
// system, so…
fn det(&self) -> f64 {
match self.dim {
0 => 0.,
1 => self[0][0],
2 => self[0][0] * self[1][1] - self[0][1] * self[1][0],
d => {
let mut acc = 0.;
let mut signature = 1.;
for k in 0..d {
acc += signature * self[0][k] * self.comatrix(0, k).det();
signature *= -1.
}
acc
}
}
}
// Solve linear systems using Cramer's method
fn solve(&self, target: &Vec<f64>) -> Vec<f64> {
let mut solution: Vec<f64> = vec![0.; self.dim];
let denominator = self.det();
for j in 0..self.dim {
let mut mm = self.clone();
for i in 0..self.dim {
mm[i][j] = target[i]
}
solution[j] = mm.det() / denominator
}
solution
}
// Compute the cofactor matrix for determinant computations
fn comatrix(&self, k: usize, l: usize) -> Matrix {
let mut v: Vec<f64> = vec![];
for i in 0..self.dim {
for j in 0..self.dim {
if i != k && j != l {
v.push(self[i][j])
}
}
}
matrix(v, self.dim - 1)
}
}
fn matrix(elts: Vec<f64>, dim: usize) -> Matrix {
assert_eq!(elts.len(), dim * dim);
Matrix { elts, dim }
}
impl Index<usize> for Matrix {
type Output = [f64];
fn index(&self, i: usize) -> &Self::Output {
let m = self.dim;
&self.elts[m * i..m * (i + 1)]
}
}
impl IndexMut<usize> for Matrix {
fn index_mut(&mut self, i: usize) -> &mut Self::Output {
let m = self.dim;
&mut self.elts[m * i..m * (i + 1)]
}
} |
http://rosettacode.org/wiki/Create_a_file | Create a file | In this task, the job is to create a new empty file called "output.txt" of size 0 bytes
and an empty directory called "docs". This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root.
| #Icon_and_Unicon | Icon and Unicon | every dir := !["./","/"] do {
close(open(f := dir || "input.txt","w")) |stop("failure for open ",f)
mkdir(f := dir || "docs") |stop("failure for mkdir ",f)
} |
http://rosettacode.org/wiki/CSV_to_HTML_translation | CSV to HTML translation | Consider a simplified CSV format where all rows are separated by a newline
and all columns are separated by commas.
No commas are allowed as field data, but the data may contain
other characters and character sequences that would
normally be escaped when converted to HTML
Task
Create a function that takes a string representation of the CSV data
and returns a text string of an HTML table representing the CSV data.
Use the following data as the CSV text to convert, and show your output.
Character,Speech
The multitude,The messiah! Show us the messiah!
Brians mother,<angry>Now you listen here! He's not the messiah; he's a very naughty boy! Now go away!</angry>
The multitude,Who are you?
Brians mother,I'm his mother; that's who!
The multitude,Behold his mother! Behold his mother!
Extra credit
Optionally allow special formatting for the first row of the table as if it is the tables header row
(via <thead> preferably; CSS if you must).
| #Java_2 | Java | String csv = "...";
// Use Collectors.joining(...) for streaming, otherwise StringJoiner
StringBuilder html = new StringBuilder("<table>\n");
Collector collector = Collectors.joining("</td><td>", " <tr><td>", "</td></tr>\n");
for (String row : csv.split("\n") ) {
html.append(Arrays.stream(row.split(",")).collect(collector));
}
html.append("</table>\n"); |
http://rosettacode.org/wiki/CSV_data_manipulation | CSV data manipulation | CSV spreadsheet files are suitable for storing tabular data in a relatively portable way.
The CSV format is flexible but somewhat ill-defined.
For present purposes, authors may assume that the data fields contain no commas, backslashes, or quotation marks.
Task
Read a CSV file, change some values and save the changes back to a file.
For this task we will use the following CSV file:
C1,C2,C3,C4,C5
1,5,9,13,17
2,6,10,14,18
3,7,11,15,19
4,8,12,16,20
Suggestions
Show how to add a column, headed 'SUM', of the sums of the rows.
If possible, illustrate the use of built-in or standard functions, methods, or libraries, that handle generic CSV files.
| #PowerShell | PowerShell | ## Create a CSV file
@"
C1,C2,C3,C4,C5
1,5,9,13,17
2,6,10,14,18
3,7,11,15,19
4,8,12,16,20
"@ -split "`r`n" | Out-File -FilePath .\Temp.csv -Force
## Import each line of the CSV file into an array of PowerShell objects
$records = Import-Csv -Path .\Temp.csv
## Sum the values of the properties of each object
$sums = $records | ForEach-Object {
[int]$sum = 0
foreach ($field in $_.PSObject.Properties.Name)
{
$sum += $_.$field
}
$sum
}
## Add a column (Sum) and its value to each object in the array
$records = for ($i = 0; $i -lt $sums.Count; $i++)
{
$records[$i] | Select-Object *,@{Name='Sum';Expression={$sums[$i]}}
}
## Export the array of modified objects to the CSV file
$records | Export-Csv -Path .\Temp.csv -Force
## Display the object in tabular form
$records | Format-Table -AutoSize
|
http://rosettacode.org/wiki/Day_of_the_week | Day of the week | A company decides that whenever Xmas falls on a Sunday they will give their workers all extra paid holidays so that, together with any public holidays, workers will not have to work the following week (between the 25th of December and the first of January).
Task
In what years between 2008 and 2121 will the 25th of December be a Sunday?
Using any standard date handling libraries of your programming language;
compare the dates calculated with the output of other languages to discover any anomalies in the handling of dates which may be due to, for example, overflow in types used to represent dates/times similar to y2k type problems.
| #SAS | SAS | data _null_;
do y=2008 to 2121;
a=mdy(12,25,y);
if weekday(a)=1 then put y;
end;
run;
/* 2011 2016 2022 2033 2039 2044 2050 2061 2067
2072 2078 2089 2095 2101 2107 2112 2118 */ |
http://rosettacode.org/wiki/Day_of_the_week | Day of the week | A company decides that whenever Xmas falls on a Sunday they will give their workers all extra paid holidays so that, together with any public holidays, workers will not have to work the following week (between the 25th of December and the first of January).
Task
In what years between 2008 and 2121 will the 25th of December be a Sunday?
Using any standard date handling libraries of your programming language;
compare the dates calculated with the output of other languages to discover any anomalies in the handling of dates which may be due to, for example, overflow in types used to represent dates/times similar to y2k type problems.
| #Scala | Scala | import java.util.{ Calendar, GregorianCalendar }
import Calendar.{ DAY_OF_WEEK, DECEMBER, SUNDAY }
object DayOfTheWeek extends App {
val years = 2008 to 2121
val yuletide =
years.filter(year => (new GregorianCalendar(year, DECEMBER, 25)).get(DAY_OF_WEEK) == SUNDAY)
// If you want a test: (optional)
assert(yuletide ==
Seq(2011, 2016, 2022, 2033, 2039, 2044, 2050, 2061,
2067, 2072, 2078, 2089, 2095, 2101, 2107, 2112, 2118))
println(yuletide.mkString(
s"${yuletide.length} Years between ${years.head} and ${years.last}" +
" including where Christmas is observed on Sunday:\n", ", ", "."))
} |
http://rosettacode.org/wiki/Create_a_two-dimensional_array_at_runtime | Create a two-dimensional array at runtime |
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
Get two integers from the user, then create a two-dimensional array where the two dimensions have the sizes given by those numbers, and which can be accessed in the most natural way possible. Write some element of that array, and then output that element. Finally destroy the array if not done by the language itself.
| #Lua | Lua | function multiply(n, a, b) if a <= b then return n, multiply(n, a + 1, b) end end
a, b = io.read() + 0, io.read() + 0
matrix = {multiply({multiply(1, 1, b)}, 1, a)}
matrix[a][b] = 5
print(matrix[a][b])
print(matrix[1][1]) |
http://rosettacode.org/wiki/Cumulative_standard_deviation | Cumulative standard deviation | Task[edit]
Write a stateful function, class, generator or co-routine that takes a series of floating point numbers, one at a time, and returns the running standard deviation of the series.
The task implementation should use the most natural programming style of those listed for the function in the implementation language; the task must state which is being used.
Do not apply Bessel's correction; the returned standard deviation should always be computed as if the sample seen so far is the entire population.
Test case
Use this to compute the standard deviation of this demonstration set,
{
2
,
4
,
4
,
4
,
5
,
5
,
7
,
9
}
{\displaystyle \{2,4,4,4,5,5,7,9\}}
, which is
2
{\displaystyle 2}
.
Related tasks
Random numbers
Tasks for calculating statistical measures
in one go
moving (sliding window)
moving (cumulative)
Mean
Arithmetic
Statistics/Basic
Averages/Arithmetic mean
Averages/Pythagorean means
Averages/Simple moving average
Geometric
Averages/Pythagorean means
Harmonic
Averages/Pythagorean means
Quadratic
Averages/Root mean square
Circular
Averages/Mean angle
Averages/Mean time of day
Median
Averages/Median
Mode
Averages/Mode
Standard deviation
Statistics/Basic
Cumulative standard deviation
| #MiniScript | MiniScript | StdDeviator = {}
StdDeviator.count = 0
StdDeviator.sum = 0
StdDeviator.sumOfSquares = 0
StdDeviator.add = function(x)
self.count = self.count + 1
self.sum = self.sum + x
self.sumOfSquares = self.sumOfSquares + x*x
end function
StdDeviator.stddev = function()
m = self.sum / self.count
return sqrt(self.sumOfSquares / self.count - m*m)
end function
sd = new StdDeviator
for x in [2, 4, 4, 4, 5, 5, 7, 9]
sd.add x
end for
print sd.stddev |
http://rosettacode.org/wiki/CRC-32 | CRC-32 |
Task
Demonstrate a method of deriving the Cyclic Redundancy Check from within the language.
The result should be in accordance with ISO 3309, ITU-T V.42, Gzip and PNG.
Algorithms are described on Computation of CRC in Wikipedia.
This variant of CRC-32 uses LSB-first order, sets the initial CRC to FFFFFFFF16, and complements the final CRC.
For the purpose of this task, generate a CRC-32 checksum for the ASCII encoded string:
The quick brown fox jumps over the lazy dog
| #Racket | Racket | #lang racket
(define (bytes-crc32 data)
(bitwise-xor
(for/fold ([accum #xFFFFFFFF])
([byte (in-bytes data)])
(for/fold ([accum (bitwise-xor accum byte)])
([num (in-range 0 8)])
(bitwise-xor (quotient accum 2)
(* #xEDB88320 (bitwise-and accum 1)))))
#xFFFFFFFF))
(define (crc32 s)
(bytes-crc32 (string->bytes/utf-8 s)))
(format "~x" (crc32 "The quick brown fox jumps over the lazy dog")) |
http://rosettacode.org/wiki/CRC-32 | CRC-32 |
Task
Demonstrate a method of deriving the Cyclic Redundancy Check from within the language.
The result should be in accordance with ISO 3309, ITU-T V.42, Gzip and PNG.
Algorithms are described on Computation of CRC in Wikipedia.
This variant of CRC-32 uses LSB-first order, sets the initial CRC to FFFFFFFF16, and complements the final CRC.
For the purpose of this task, generate a CRC-32 checksum for the ASCII encoded string:
The quick brown fox jumps over the lazy dog
| #Raku | Raku | use NativeCall;
sub crc32(int32 $crc, Buf $buf, int32 $len --> int32) is native('z') { * }
my $buf = 'The quick brown fox jumps over the lazy dog'.encode;
say crc32(0, $buf, $buf.bytes).fmt('%08x'); |
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