task_url stringlengths 30 116 | task_name stringlengths 2 86 | task_description stringlengths 0 14.4k | language_url stringlengths 2 53 | language_name stringlengths 1 52 | code stringlengths 0 61.9k |
|---|---|---|---|---|---|
http://rosettacode.org/wiki/Empty_directory | Empty directory | Starting with a path to some directory, determine whether the directory is empty.
An empty directory contains no files nor subdirectories.
With Unix or Windows systems, every directory contains an entry for “.” and almost every directory contains “..” (except for a root directory); an empty directory contains no other... | #Groovy | Groovy | def isDirEmpty = { dirName ->
def dir = new File(dirName)
dir.exists() && dir.directory && (dir.list() as List).empty
} |
http://rosettacode.org/wiki/Empty_program | Empty program | Task
Create the simplest possible program that is still considered "correct."
| #ArnoldC | ArnoldC | IT'S SHOWTIME
YOU HAVE BEEN TERMINATED |
http://rosettacode.org/wiki/Empty_program | Empty program | Task
Create the simplest possible program that is still considered "correct."
| #Arturo | Arturo | |
http://rosettacode.org/wiki/Enforced_immutability | Enforced immutability | Task
Demonstrate any means your language has to prevent the modification of values, or to create objects that cannot be modified after they have been created.
| #Ring | Ring |
# Project : Enforced immutability
x = 10
assert( x = 10)
assert( x = 100 )
|
http://rosettacode.org/wiki/Enforced_immutability | Enforced immutability | Task
Demonstrate any means your language has to prevent the modification of values, or to create objects that cannot be modified after they have been created.
| #Ruby | Ruby | msg = "Hello World"
msg << "!"
puts msg #=> Hello World!
puts msg.frozen? #=> false
msg.freeze
puts msg.frozen? #=> true
begin
msg << "!"
rescue => e
p e #=> #<RuntimeError: can't modify frozen String>
end
puts msg #=> Hello World!
msg2 = msg
# The... |
http://rosettacode.org/wiki/Enforced_immutability | Enforced immutability | Task
Demonstrate any means your language has to prevent the modification of values, or to create objects that cannot be modified after they have been created.
| #Rust | Rust | let x = 3;
x += 2; |
http://rosettacode.org/wiki/Enforced_immutability | Enforced immutability | Task
Demonstrate any means your language has to prevent the modification of values, or to create objects that cannot be modified after they have been created.
| #Scala | Scala | val pi = 3.14159
val msg = "Hello World" |
http://rosettacode.org/wiki/Entropy | Entropy | Task
Calculate the Shannon entropy H of a given input string.
Given the discrete random variable
X
{\displaystyle X}
that is a string of
N
{\displaystyle N}
"symbols" (total characters) consisting of
n
{\displaystyle n}
different characters (n=2 for binary), the Shannon entropy of X in bit... | #Crystal | Crystal | # Method to calculate sum of Float64 array
def sum(array : Array(Float64))
res = 0
array.each do |n|
res += n
end
res
end
# Method to calculate which char appears how often
def histogram(source : String)
hist = {} of Char => Int32
l = 0
source.each_char do |e|
if !hist.has_key? e
hist[e] =... |
http://rosettacode.org/wiki/Ethiopian_multiplication | Ethiopian multiplication | Ethiopian multiplication is a method of multiplying integers using only addition, doubling, and halving.
Method:
Take two numbers to be multiplied and write them down at the top of two columns.
In the left-hand column repeatedly halve the last number, discarding any remainders, and write the result below the last ... | #CoffeeScript | CoffeeScript |
halve = (n) -> Math.floor n / 2
double = (n) -> n * 2
is_even = (n) -> n % 2 == 0
multiply = (a, b) ->
prod = 0
while a > 0
prod += b if !is_even a
a = halve a
b = double b
prod
# tests
do ->
for i in [0..100]
for j in [0..100]
throw Error("broken for #{i} * #{j}") if multiply(i,j) !... |
http://rosettacode.org/wiki/Equilibrium_index | Equilibrium index | An equilibrium index of a sequence is an index into the sequence such that the sum of elements at lower indices is equal to the sum of elements at higher indices.
For example, in a sequence
A
{\displaystyle A}
:
A
0
=
−
7
{\displaystyle A_{0}=-7}
A
1
=
1
{\displaystyle A_{1}=1}
... | #jq | jq | # The index origin is 0 in jq.
def equilibrium_indices:
def indices(a; mx):
def report: # [i, headsum, tailsum]
.[0] as $i
| if $i == mx then empty # all done
else .[1] as $h
| (.[2] - a[$i]) as $t
| (if $h == $t then $i else empty end),
( [ $i + 1, $h + a[$... |
http://rosettacode.org/wiki/Equilibrium_index | Equilibrium index | An equilibrium index of a sequence is an index into the sequence such that the sum of elements at lower indices is equal to the sum of elements at higher indices.
For example, in a sequence
A
{\displaystyle A}
:
A
0
=
−
7
{\displaystyle A_{0}=-7}
A
1
=
1
{\displaystyle A_{1}=1}
... | #Julia | Julia | function equindex2pass(data::Array)
rst = Vector{Int}(0)
suml, sumr, ddelayed = 0, sum(data), 0
for (i, d) in enumerate(data)
suml += ddelayed
sumr -= d
ddelayed = d
if suml == sumr
push!(rst, i)
end
end
return rst
end
@show equindex2pass([1, -1,... |
http://rosettacode.org/wiki/Environment_variables | Environment variables | Task
Show how to get one of your process's environment variables.
The available variables vary by system; some of the common ones available on Unix include:
PATH
HOME
USER
| #OCaml | OCaml | Sys.getenv "HOME" |
http://rosettacode.org/wiki/Environment_variables | Environment variables | Task
Show how to get one of your process's environment variables.
The available variables vary by system; some of the common ones available on Unix include:
PATH
HOME
USER
| #Oforth | Oforth | System getEnv("PATH") println |
http://rosettacode.org/wiki/Environment_variables | Environment variables | Task
Show how to get one of your process's environment variables.
The available variables vary by system; some of the common ones available on Unix include:
PATH
HOME
USER
| #Oz | Oz | {System.showInfo "This is where Mozart is installed: "#{OS.getEnv 'OZHOME'}} |
http://rosettacode.org/wiki/Environment_variables | Environment variables | Task
Show how to get one of your process's environment variables.
The available variables vary by system; some of the common ones available on Unix include:
PATH
HOME
USER
| #PARI.2FGP | PARI/GP | getenv("HOME") |
http://rosettacode.org/wiki/Euler%27s_sum_of_powers_conjecture | Euler's sum of powers conjecture | There is a conjecture in mathematics that held for over two hundred years before it was disproved by the finding of a counterexample in 1966 by Lander and Parkin.
Euler's (disproved) sum of powers conjecture
At least k positive kth powers are required to sum to a kth power,
except for the trivial case... | #Haskell | Haskell | import Data.List
import Data.List.Ordered
main :: IO ()
main = print $ head [(x0,x1,x2,x3,x4) |
-- choose x0, x1, x2, x3
-- so that 250 < x3 < x2 < x1 < x0
x3 <- [1..250-1],
... |
http://rosettacode.org/wiki/Factorial | Factorial | Definitions
The factorial of 0 (zero) is defined as being 1 (unity).
The Factorial Function of a positive integer, n, is defined as the product of the sequence:
n, n-1, n-2, ... 1
Task
Write a function to return the factorial of a number.
Solutions can be iterat... | #Oberon | Oberon |
MODULE Factorial;
IMPORT
Out;
VAR
i: INTEGER;
PROCEDURE Iterative(n: LONGINT): LONGINT;
VAR
i, r: LONGINT;
BEGIN
ASSERT(n >= 0);
r := 1;
FOR i := n TO 2 BY -1 DO
r := r * i
END;
RETURN r
END Iterative;
PROCEDURE Recursive(n: LONGINT): LONGINT;
VAR
r: LONGINT;
... |
http://rosettacode.org/wiki/Even_or_odd | Even or odd | Task
Test whether an integer is even or odd.
There is more than one way to solve this task:
Use the even and odd predicates, if the language provides them.
Check the least significant digit. With binary integers, i bitwise-and 1 equals 0 iff i is even, or equals 1 iff i is odd.
Divide i by 2. The remainder equals... | #Component_Pascal | Component Pascal |
MODULE EvenOdd;
IMPORT StdLog,Args,Strings;
PROCEDURE BitwiseOdd(i: INTEGER): BOOLEAN;
BEGIN
RETURN 0 IN BITS(i)
END BitwiseOdd;
PROCEDURE Odd(i: INTEGER): BOOLEAN;
BEGIN
RETURN (i MOD 2) # 0
END Odd;
PROCEDURE CongruenceOdd(i: INTEGER): BOOLEAN;
BEGIN
RETURN ((i -1) MOD 2) = 0
END CongruenceOdd;
PROCEDURE... |
http://rosettacode.org/wiki/Euler_method | Euler method | Euler's method numerically approximates solutions of first-order ordinary differential equations (ODEs) with a given initial value. It is an explicit method for solving initial value problems (IVPs), as described in the wikipedia page.
The ODE has to be provided in the following form:
d
y
(
t
)
d
t
=
f... | #Smalltalk | Smalltalk | ODESolver>>eulerOf: f init: y0 from: a to: b step: h
| t y |
t := a.
y := y0.
[ t < b ]
whileTrue: [
Transcript
show: t asString, ' ' , (y printShowingDecimalPlaces: 3);
cr.
t := t + h.
y := y + (h * (f value: t value: y)) ]
ODESolver new eulerOf: [:time :temp| -0.07 * (temp - 20)] init: 100 ... |
http://rosettacode.org/wiki/Evaluate_binomial_coefficients | Evaluate binomial coefficients | This programming task, is to calculate ANY binomial coefficient.
However, it has to be able to output
(
5
3
)
{\displaystyle {\binom {5}{3}}}
, which is 10.
This formula is recommended:
(
n
k
)
=
n
!
(
n
−
k
)
!
k
!
=
n
(
n
−
1
)
(
n
−
2
)
…
(
n
−
k
+
1
)
k
(
k
−
1... | #Lasso | Lasso | define binomial(n::integer,k::integer) => {
#k == 0 ? return 1
local(result = 1)
loop(#k) => {
#result = #result * (#n - loop_count + 1) / loop_count
}
return #result
}
// Tests
binomial(5, 3)
binomial(5, 4)
binomial(60, 30) |
http://rosettacode.org/wiki/Evaluate_binomial_coefficients | Evaluate binomial coefficients | This programming task, is to calculate ANY binomial coefficient.
However, it has to be able to output
(
5
3
)
{\displaystyle {\binom {5}{3}}}
, which is 10.
This formula is recommended:
(
n
k
)
=
n
!
(
n
−
k
)
!
k
!
=
n
(
n
−
1
)
(
n
−
2
)
…
(
n
−
k
+
1
)
k
(
k
−
1... | #Liberty_BASIC | Liberty BASIC |
' [RC] Binomial Coefficients
print "Binomial Coefficient of "; 5; " and "; 3; " is ",BinomialCoefficient( 5, 3)
n =1 +int( 10 *rnd( 1))
k =1 +int( n *rnd( 1))
print "Binomial Coefficient of "; n; " and "; k; " is ",BinomialCoefficient( n, k)
end
function BinomialCoefficient( n, k)
... |
http://rosettacode.org/wiki/Emirp_primes | Emirp primes | An emirp (prime spelled backwards) are primes that when reversed (in their decimal representation) are a different prime.
(This rules out palindromic primes.)
Task
show the first twenty emirps
show all emirps between 7,700 and 8,000
show the 10,000th emirp
In each list, the numbe... | #C.2B.2B | C++ | #include <vector>
#include <iostream>
#include <algorithm>
#include <sstream>
#include <string>
#include <cmath>
bool isPrime ( int number ) {
if ( number <= 1 )
return false ;
if ( number == 2 )
return true ;
for ( int i = 2 ; i <= std::sqrt( number ) ; i++ ) {
if ( number % i == 0 )
re... |
http://rosettacode.org/wiki/Elliptic_curve_arithmetic | Elliptic curve arithmetic | Elliptic curves are sometimes used in cryptography as a way to perform digital signatures.
The purpose of this task is to implement a simplified (without modular arithmetic) version of the elliptic curve arithmetic which is required by the elliptic curve DSA protocol.
In a nutshell, an elliptic curve is a... | #PARI.2FGP | PARI/GP | e=ellinit([0,7]);
a=[-6^(1/3),1]
b=[-3^(1/3),2]
c=elladd(e,a,b)
d=ellneg(e,c)
elladd(e,c,d)
elladd(e,elladd(e,a,b),d)
ellmul(e,a,12345) |
http://rosettacode.org/wiki/Elliptic_curve_arithmetic | Elliptic curve arithmetic | Elliptic curves are sometimes used in cryptography as a way to perform digital signatures.
The purpose of this task is to implement a simplified (without modular arithmetic) version of the elliptic curve arithmetic which is required by the elliptic curve DSA protocol.
In a nutshell, an elliptic curve is a... | #Perl | Perl | package EC;
{
our ($A, $B) = (0, 7);
package EC::Point;
sub new { my $class = shift; bless [ @_ ], $class }
sub zero { bless [], shift }
sub x { shift->[0] }; sub y { shift->[1] };
sub double {
my $self = shift;
return $self unless @$self;
my $L = (3 * $self->x**2) / (2*$... |
http://rosettacode.org/wiki/Enumerations | Enumerations | Task
Create an enumeration of constants with and without explicit values.
| #Metafont | Metafont | vardef enum(expr first)(text t) =
save ?; ? := first;
forsuffixes e := t: e := ?; ?:=?+1; endfor
enddef; |
http://rosettacode.org/wiki/Enumerations | Enumerations | Task
Create an enumeration of constants with and without explicit values.
| #Modula-3 | Modula-3 | TYPE Fruit = {Apple, Banana, Cherry}; |
http://rosettacode.org/wiki/Enumerations | Enumerations | Task
Create an enumeration of constants with and without explicit values.
| #Nemerle | Nemerle | enum Fruit {
|apple
|banana
|cherry
}
enum Season {
|winter = 1
|spring = 2
|summer = 3
|autumn = 4
} |
http://rosettacode.org/wiki/Elementary_cellular_automaton/Random_Number_Generator | Elementary cellular automaton/Random Number Generator | Rule 30 is considered to be chaotic enough to generate good pseudo-random numbers. As a matter of fact, rule 30 is used by the Mathematica software for its default random number generator.
Steven Wolfram's recommendation for random number generation from rule 30 consists in extracting successive bits in a fixed positi... | #Ruby | Ruby | size = 100
eca = ElemCellAutomat.new("1"+"0"*(size-1), 30)
eca.take(80).map{|line| line[0]}.each_slice(8){|bin| p bin.join.to_i(2)} |
http://rosettacode.org/wiki/Elementary_cellular_automaton/Random_Number_Generator | Elementary cellular automaton/Random Number Generator | Rule 30 is considered to be chaotic enough to generate good pseudo-random numbers. As a matter of fact, rule 30 is used by the Mathematica software for its default random number generator.
Steven Wolfram's recommendation for random number generation from rule 30 consists in extracting successive bits in a fixed positi... | #Rust | Rust |
//Assuming the code from the Elementary cellular automaton task is in the namespace.
fn main() {
struct WolfGen(ElementaryCA);
impl WolfGen {
fn new() -> WolfGen {
let (_, ca) = ElementaryCA::new(30);
WolfGen(ca)
}
fn next(&mut self) -> u8 {
let mut ... |
http://rosettacode.org/wiki/Elementary_cellular_automaton/Random_Number_Generator | Elementary cellular automaton/Random Number Generator | Rule 30 is considered to be chaotic enough to generate good pseudo-random numbers. As a matter of fact, rule 30 is used by the Mathematica software for its default random number generator.
Steven Wolfram's recommendation for random number generation from rule 30 consists in extracting successive bits in a fixed positi... | #Scheme | Scheme |
; uses SRFI-1 library http://srfi.schemers.org/srfi-1/srfi-1.html
(define (random-r30 n)
(let ((r30 (vector 0 1 1 1 1 0 0 0)))
(fold
(lambda (x y ls)
(if (= x 1)
(cons (* x y) ls)
(cons (+ (car ls) (* x y)) (cdr ls))))
'()
(circular-list 1 2 4 8 16 32 64 128)
(unfold-right
(lam... |
http://rosettacode.org/wiki/Empty_string | Empty string | Languages may have features for dealing specifically with empty strings
(those containing no characters).
Task
Demonstrate how to assign an empty string to a variable.
Demonstrate how to check that a string is empty.
Demonstrate how to check that a string is not empty.
Other tasks related to string oper... | #BASIC | BASIC | 10 LET A$=""
20 IF A$="" THEN PRINT "THE STRING IS EMPTY"
30 IF A$<>"" THEN PRINT "THE STRING IS NOT EMPTY"
40 END |
http://rosettacode.org/wiki/Empty_string | Empty string | Languages may have features for dealing specifically with empty strings
(those containing no characters).
Task
Demonstrate how to assign an empty string to a variable.
Demonstrate how to check that a string is empty.
Demonstrate how to check that a string is not empty.
Other tasks related to string oper... | #Batch_File | Batch File |
@echo off
::set "var" as a blank string.
set var=
::check if "var" is a blank string.
if not defined var echo Var is a blank string.
::Alternatively,
if %var%@ equ @ echo Var is a blank string.
::check if "var" is not a blank string.
if defined var echo Var is defined.
::Alternatively,
if %var%@ neq @ echo Var is ... |
http://rosettacode.org/wiki/Empty_directory | Empty directory | Starting with a path to some directory, determine whether the directory is empty.
An empty directory contains no files nor subdirectories.
With Unix or Windows systems, every directory contains an entry for “.” and almost every directory contains “..” (except for a root directory); an empty directory contains no other... | #Haskell | Haskell | import System.Directory (getDirectoryContents)
import System.Environment (getArgs)
isEmpty x = getDirectoryContents x >>= return . f . (== [".", ".."])
where f True = "Directory is empty"
f False = "Directory is not empty"
main = getArgs >>= isEmpty . (!! 0) >>= putStrLn |
http://rosettacode.org/wiki/Empty_directory | Empty directory | Starting with a path to some directory, determine whether the directory is empty.
An empty directory contains no files nor subdirectories.
With Unix or Windows systems, every directory contains an entry for “.” and almost every directory contains “..” (except for a root directory); an empty directory contains no other... | #Icon_and_Unicon | Icon and Unicon | procedure main()
every dir := "." | "./empty" do
write(dir, if isdirempty(dir) then " is empty" else " is not empty")
end
procedure isdirempty(s) #: succeeds if directory s is empty (and a directory)
local d,f
if ( stat(s).mode ? ="d" ) & ( d := open(s) ) then {
while f := read(d) do
... |
http://rosettacode.org/wiki/Empty_program | Empty program | Task
Create the simplest possible program that is still considered "correct."
| #Asymptote | Asymptote | |
http://rosettacode.org/wiki/Empty_program | Empty program | Task
Create the simplest possible program that is still considered "correct."
| #AutoHotkey | AutoHotkey | #Persistent |
http://rosettacode.org/wiki/Enforced_immutability | Enforced immutability | Task
Demonstrate any means your language has to prevent the modification of values, or to create objects that cannot be modified after they have been created.
| #Scheme | Scheme | (define-syntax define-constant
(syntax-rules ()
((_ id v)
(begin
(define _id v)
(define-syntax id
(make-variable-transformer
(lambda (stx)
(syntax-case stx (set!)
((set! id _)
(raise
(syntax-violation
'... |
http://rosettacode.org/wiki/Enforced_immutability | Enforced immutability | Task
Demonstrate any means your language has to prevent the modification of values, or to create objects that cannot be modified after they have been created.
| #Seed7 | Seed7 | const integer: foo is 42;
const string: bar is "bar";
const blahtype: blah is blahvalue; |
http://rosettacode.org/wiki/Enforced_immutability | Enforced immutability | Task
Demonstrate any means your language has to prevent the modification of values, or to create objects that cannot be modified after they have been created.
| #Sidef | Sidef | define PI = 3.14159; # compile-time defined constant
const MSG = "Hello world!"; # run-time defined constant |
http://rosettacode.org/wiki/Enforced_immutability | Enforced immutability | Task
Demonstrate any means your language has to prevent the modification of values, or to create objects that cannot be modified after they have been created.
| #SuperCollider | SuperCollider | // you can freeze any object.
b = [1, 2, 3];
b[1] = 100; // returns [1, 100, 3]
b.freeze; // make b immutable
b[1] = 2; // throws an error ("Attempted write to immutable object.") |
http://rosettacode.org/wiki/Entropy | Entropy | Task
Calculate the Shannon entropy H of a given input string.
Given the discrete random variable
X
{\displaystyle X}
that is a string of
N
{\displaystyle N}
"symbols" (total characters) consisting of
n
{\displaystyle n}
different characters (n=2 for binary), the Shannon entropy of X in bit... | #D | D | import std.stdio, std.algorithm, std.math;
double entropy(T)(T[] s)
pure nothrow if (__traits(compiles, s.sort())) {
immutable sLen = s.length;
return s
.sort()
.group
.map!(g => g[1] / double(sLen))
.map!(p => -p * p.log2)
.sum;
}
void main() {
"12... |
http://rosettacode.org/wiki/Ethiopian_multiplication | Ethiopian multiplication | Ethiopian multiplication is a method of multiplying integers using only addition, doubling, and halving.
Method:
Take two numbers to be multiplied and write them down at the top of two columns.
In the left-hand column repeatedly halve the last number, discarding any remainders, and write the result below the last ... | #ColdFusion | ColdFusion | <cffunction name="double">
<cfargument name="number" type="numeric" required="true">
<cfset answer = number * 2>
<cfreturn answer>
</cffunction>
<cffunction name="halve">
<cfargument name="number" type="numeric" required="true">
<cfset answer = int(number / 2)>
<cfreturn answer>
</cffunction>
<cff... |
http://rosettacode.org/wiki/Equilibrium_index | Equilibrium index | An equilibrium index of a sequence is an index into the sequence such that the sum of elements at lower indices is equal to the sum of elements at higher indices.
For example, in a sequence
A
{\displaystyle A}
:
A
0
=
−
7
{\displaystyle A_{0}=-7}
A
1
=
1
{\displaystyle A_{1}=1}
... | #K | K | f:{&{(+/y# x)=+/(y+1)_x}[x]'!#x}
f -7 1 5 2 -4 3 0
3 6
f 2 4 6
!0
f 2 9 2
,1
f 1 -1 1 -1 1 -1 1
0 1 2 3 4 5 6 |
http://rosettacode.org/wiki/Equilibrium_index | Equilibrium index | An equilibrium index of a sequence is an index into the sequence such that the sum of elements at lower indices is equal to the sum of elements at higher indices.
For example, in a sequence
A
{\displaystyle A}
:
A
0
=
−
7
{\displaystyle A_{0}=-7}
A
1
=
1
{\displaystyle A_{1}=1}
... | #Kotlin | Kotlin | // version 1.1
fun equilibriumIndices(a: IntArray): MutableList<Int> {
val ei = mutableListOf<Int>()
if (a.isEmpty()) return ei // empty list
val sumAll = a.sumBy { it }
var sumLeft = 0
var sumRight: Int
for (i in 0 until a.size) {
sumRight = sumAll - sumLeft - a[i]
if (sumLeft == sum... |
http://rosettacode.org/wiki/Environment_variables | Environment variables | Task
Show how to get one of your process's environment variables.
The available variables vary by system; some of the common ones available on Unix include:
PATH
HOME
USER
| #Perl | Perl | print $ENV{HOME}, "\n"; |
http://rosettacode.org/wiki/Environment_variables | Environment variables | Task
Show how to get one of your process's environment variables.
The available variables vary by system; some of the common ones available on Unix include:
PATH
HOME
USER
| #Phix | Phix | without js -- none such in a browser, that I know of
?getenv("PATH")
|
http://rosettacode.org/wiki/Environment_variables | Environment variables | Task
Show how to get one of your process's environment variables.
The available variables vary by system; some of the common ones available on Unix include:
PATH
HOME
USER
| #PHP | PHP | $_ENV['HOME'] |
http://rosettacode.org/wiki/Environment_variables | Environment variables | Task
Show how to get one of your process's environment variables.
The available variables vary by system; some of the common ones available on Unix include:
PATH
HOME
USER
| #PicoLisp | PicoLisp | : (sys "TERM")
-> "xterm"
: (sys "SHELL")
-> "/bin/bash" |
http://rosettacode.org/wiki/Euler%27s_sum_of_powers_conjecture | Euler's sum of powers conjecture | There is a conjecture in mathematics that held for over two hundred years before it was disproved by the finding of a counterexample in 1966 by Lander and Parkin.
Euler's (disproved) sum of powers conjecture
At least k positive kth powers are required to sum to a kth power,
except for the trivial case... | #J | J | require 'stats'
(#~ (= <.)@((+/"1)&.:(^&5)))1+4 comb 248
27 84 110 133 |
http://rosettacode.org/wiki/Factorial | Factorial | Definitions
The factorial of 0 (zero) is defined as being 1 (unity).
The Factorial Function of a positive integer, n, is defined as the product of the sequence:
n, n-1, n-2, ... 1
Task
Write a function to return the factorial of a number.
Solutions can be iterat... | #Objeck | Objeck | bundle Default {
class Fact {
function : Main(args : String[]) ~ Nil {
5->Factorial()->PrintLine();
}
}
} |
http://rosettacode.org/wiki/Even_or_odd | Even or odd | Task
Test whether an integer is even or odd.
There is more than one way to solve this task:
Use the even and odd predicates, if the language provides them.
Check the least significant digit. With binary integers, i bitwise-and 1 equals 0 iff i is even, or equals 1 iff i is odd.
Divide i by 2. The remainder equals... | #Crystal | Crystal | #Using bitwise shift
def isEven_bShift(n)
n == ((n >> 1) << 1)
end
def isOdd_bShift(n)
n != ((n >> 1) << 1)
end
#Using modulo operator
def isEven_mod(n)
(n % 2) == 0
end
def isOdd_mod(n)
(n % 2) != 0
end
# Using bitwise "and"
def isEven_bAnd(n)
(n & 1) == 0
end
def isOdd_bAnd(... |
http://rosettacode.org/wiki/Even_or_odd | Even or odd | Task
Test whether an integer is even or odd.
There is more than one way to solve this task:
Use the even and odd predicates, if the language provides them.
Check the least significant digit. With binary integers, i bitwise-and 1 equals 0 iff i is even, or equals 1 iff i is odd.
Divide i by 2. The remainder equals... | #D | D | void main() {
import std.stdio, std.bigint;
foreach (immutable i; -5 .. 6)
writeln(i, " ", i & 1, " ", i % 2, " ", i.BigInt % 2);
} |
http://rosettacode.org/wiki/Euler_method | Euler method | Euler's method numerically approximates solutions of first-order ordinary differential equations (ODEs) with a given initial value. It is an explicit method for solving initial value problems (IVPs), as described in the wikipedia page.
The ODE has to be provided in the following form:
d
y
(
t
)
d
t
=
f... | #Swift | Swift | import Foundation
let numberFormat = " %7.3f"
let k = 0.07
let initialTemp = 100.0
let finalTemp = 20.0
let startTime = 0
let endTime = 100
func ivpEuler(function: (Double, Double) -> Double, initialValue: Double, step: Int) {
print(String(format: " Step %2d: ", step), terminator: "")
var y = initialValue
... |
http://rosettacode.org/wiki/Euler_method | Euler method | Euler's method numerically approximates solutions of first-order ordinary differential equations (ODEs) with a given initial value. It is an explicit method for solving initial value problems (IVPs), as described in the wikipedia page.
The ODE has to be provided in the following form:
d
y
(
t
)
d
t
=
f... | #Tcl | Tcl | proc euler {f y0 a b h} {
puts "computing $f over \[$a..$b\], step $h"
set y [expr {double($y0)}]
for {set t [expr {double($a)}]} {$t < $b} {set t [expr {$t + $h}]} {
puts [format "%.3f\t%.3f" $t $y]
set y [expr {$y + $h * double([$f $t $y])}]
}
puts "done"
} |
http://rosettacode.org/wiki/Evaluate_binomial_coefficients | Evaluate binomial coefficients | This programming task, is to calculate ANY binomial coefficient.
However, it has to be able to output
(
5
3
)
{\displaystyle {\binom {5}{3}}}
, which is 10.
This formula is recommended:
(
n
k
)
=
n
!
(
n
−
k
)
!
k
!
=
n
(
n
−
1
)
(
n
−
2
)
…
(
n
−
k
+
1
)
k
(
k
−
1... | #Logo | Logo | to choose :n :k
if :k = 0 [output 1]
output (choose :n :k-1) * (:n - :k + 1) / :k
end
show choose 5 3 ; 10
show choose 60 30 ; 1.18264581564861e+17 |
http://rosettacode.org/wiki/Evaluate_binomial_coefficients | Evaluate binomial coefficients | This programming task, is to calculate ANY binomial coefficient.
However, it has to be able to output
(
5
3
)
{\displaystyle {\binom {5}{3}}}
, which is 10.
This formula is recommended:
(
n
k
)
=
n
!
(
n
−
k
)
!
k
!
=
n
(
n
−
1
)
(
n
−
2
)
…
(
n
−
k
+
1
)
k
(
k
−
1... | #Lua | Lua | function Binomial( n, k )
if k > n then return nil end
if k > n/2 then k = n - k end -- (n k) = (n n-k)
numer, denom = 1, 1
for i = 1, k do
numer = numer * ( n - i + 1 )
denom = denom * i
end
return numer / denom
end |
http://rosettacode.org/wiki/Emirp_primes | Emirp primes | An emirp (prime spelled backwards) are primes that when reversed (in their decimal representation) are a different prime.
(This rules out palindromic primes.)
Task
show the first twenty emirps
show all emirps between 7,700 and 8,000
show the 10,000th emirp
In each list, the numbe... | #Clojure | Clojure | (defn emirp? [v]
(let [a (biginteger v)
b (biginteger (clojure.string/reverse (str v)))]
(and (not= a b)
(.isProbablePrime a 16)
(.isProbablePrime b 16))))
; Generate the output
(println "first20: " (clojure.string/join " " (take 20 (filter emirp? (iterate inc 0)))))
(println "7700-... |
http://rosettacode.org/wiki/Elliptic_curve_arithmetic | Elliptic curve arithmetic | Elliptic curves are sometimes used in cryptography as a way to perform digital signatures.
The purpose of this task is to implement a simplified (without modular arithmetic) version of the elliptic curve arithmetic which is required by the elliptic curve DSA protocol.
In a nutshell, an elliptic curve is a... | #Phix | Phix | with javascript_semantics
constant X=1, Y=2, bCoeff=7, INF = 1e300*1e300
type point(object pt)
return sequence(pt) and length(pt)=2 and atom(pt[X]) and atom(pt[Y])
end type
function zero()
point pt = {INF, INF}
return pt
end function
function is_zero(point p)
return p[X]>1e20 or p[X]<-1e20
end fun... |
http://rosettacode.org/wiki/Enumerations | Enumerations | Task
Create an enumeration of constants with and without explicit values.
| #Nim | Nim | # Simple declaration.
type Fruits1 = enum aApple, aBanana, aCherry
# Specifying values (accessible using "ord").
type Fruits2 = enum bApple = 0, bBanana = 2, bCherry = 5
# Enumerations with a scope which prevent name conflict.
type Fruits3 {.pure.} = enum Apple, Banana, Cherry
type Fruits4 {.pure.} = enum Apple = 3... |
http://rosettacode.org/wiki/Enumerations | Enumerations | Task
Create an enumeration of constants with and without explicit values.
| #Objeck | Objeck |
enum Color := -3 {
Red,
White,
Blue
}
enum Dog {
Pug,
Boxer,
Terrier
}
|
http://rosettacode.org/wiki/Enumerations | Enumerations | Task
Create an enumeration of constants with and without explicit values.
| #Objective-C | Objective-C | typedef NS_ENUM(NSInteger, fruits) { apple, banana, cherry };
typedef NS_ENUM(NSInteger, fruits) { apple = 0, banana = 1, cherry = 2 }; |
http://rosettacode.org/wiki/Elementary_cellular_automaton/Random_Number_Generator | Elementary cellular automaton/Random Number Generator | Rule 30 is considered to be chaotic enough to generate good pseudo-random numbers. As a matter of fact, rule 30 is used by the Mathematica software for its default random number generator.
Steven Wolfram's recommendation for random number generation from rule 30 consists in extracting successive bits in a fixed positi... | #Sidef | Sidef | var auto = Automaton(30, [1] + 100.of(0));
10.times {
var sum = 0;
8.times {
sum = (2*sum + auto.cells[0]);
auto.next;
};
say sum;
}; |
http://rosettacode.org/wiki/Elementary_cellular_automaton/Random_Number_Generator | Elementary cellular automaton/Random Number Generator | Rule 30 is considered to be chaotic enough to generate good pseudo-random numbers. As a matter of fact, rule 30 is used by the Mathematica software for its default random number generator.
Steven Wolfram's recommendation for random number generation from rule 30 consists in extracting successive bits in a fixed positi... | #Tcl | Tcl | oo::class create RandomGenerator {
superclass ElementaryAutomaton
variable s
constructor {stateLength} {
next 30
set s [split 1[string repeat 0 $stateLength] ""]
}
method rand {} {
set bits {}
while {[llength $bits] < 8} {
lappend bits [lindex $s 0]
set s [my evolve $s]
}
return [s... |
http://rosettacode.org/wiki/Elementary_cellular_automaton/Random_Number_Generator | Elementary cellular automaton/Random Number Generator | Rule 30 is considered to be chaotic enough to generate good pseudo-random numbers. As a matter of fact, rule 30 is used by the Mathematica software for its default random number generator.
Steven Wolfram's recommendation for random number generation from rule 30 consists in extracting successive bits in a fixed positi... | #Wren | Wren | import "/big" for BigInt
var n = 64
var pow2 = Fn.new { |x| BigInt.one << x }
var evolve = Fn.new { |state, rule|
for (p in 0..9) {
var b = BigInt.zero
for (q in 7..0) {
var st = state.copy()
b = b | ((st & 1) << q)
state = BigInt.zero
for (i in ... |
http://rosettacode.org/wiki/Empty_string | Empty string | Languages may have features for dealing specifically with empty strings
(those containing no characters).
Task
Demonstrate how to assign an empty string to a variable.
Demonstrate how to check that a string is empty.
Demonstrate how to check that a string is not empty.
Other tasks related to string oper... | #BBC_BASIC | BBC BASIC | REM assign an empty string to a variable:
var$ = ""
REM Check that a string is empty:
IF var$ = "" THEN PRINT "String is empty"
REM Check that a string is not empty:
IF var$ <> "" THEN PRINT "String is not empty"
|
http://rosettacode.org/wiki/Empty_string | Empty string | Languages may have features for dealing specifically with empty strings
(those containing no characters).
Task
Demonstrate how to assign an empty string to a variable.
Demonstrate how to check that a string is empty.
Demonstrate how to check that a string is not empty.
Other tasks related to string oper... | #BQN | BQN | •Show ""
•Show 0 = ≠ ""
•Show 0 ≠ ≠ ""
•Show "" ≡ ⟨⟩ |
http://rosettacode.org/wiki/Empty_directory | Empty directory | Starting with a path to some directory, determine whether the directory is empty.
An empty directory contains no files nor subdirectories.
With Unix or Windows systems, every directory contains an entry for “.” and almost every directory contains “..” (except for a root directory); an empty directory contains no other... | #J | J | require 'dir'
empty_dir=: 0 = '/*' #@dir@,~ ] |
http://rosettacode.org/wiki/Empty_directory | Empty directory | Starting with a path to some directory, determine whether the directory is empty.
An empty directory contains no files nor subdirectories.
With Unix or Windows systems, every directory contains an entry for “.” and almost every directory contains “..” (except for a root directory); an empty directory contains no other... | #Java | Java | import java.nio.file.Paths;
//... other class code here
public static boolean isEmptyDir(String dirName){
return Paths.get(dirName).toFile().listFiles().length == 0;
} |
http://rosettacode.org/wiki/Empty_directory | Empty directory | Starting with a path to some directory, determine whether the directory is empty.
An empty directory contains no files nor subdirectories.
With Unix or Windows systems, every directory contains an entry for “.” and almost every directory contains “..” (except for a root directory); an empty directory contains no other... | #JavaScript | JavaScript | // Node.js v14.15.4
const { readdirSync } = require("fs");
const emptydir = (path) => readdirSync(path).length == 0;
// tests, run like node emptydir.js [directories]
for (let i = 2; i < process.argv.length; i ++) {
let dir = process.argv[i];
console.log(`${dir}: ${emptydir(dir) ? "" : "not "}empty`)
} |
http://rosettacode.org/wiki/Empty_program | Empty program | Task
Create the simplest possible program that is still considered "correct."
| #AutoIt | AutoIt | ;nothing |
http://rosettacode.org/wiki/Empty_program | Empty program | Task
Create the simplest possible program that is still considered "correct."
| #Avail | Avail | Module "a"
Body |
http://rosettacode.org/wiki/Enforced_immutability | Enforced immutability | Task
Demonstrate any means your language has to prevent the modification of values, or to create objects that cannot be modified after they have been created.
| #Swift | Swift | let a = 1
a = 1 // error: a is immutable
var b = 1
b = 1 |
http://rosettacode.org/wiki/Enforced_immutability | Enforced immutability | Task
Demonstrate any means your language has to prevent the modification of values, or to create objects that cannot be modified after they have been created.
| #Tcl | Tcl | proc constant {varName {value ""}} {
upvar 1 $varName var
# Allow application of immutability to an existing variable, e.g., a procedure argument
if {[llength [info frame 0]] == 2} {set value $var} else {set var $value}
trace add variable var write [list apply {{val v1 v2 op} {
upvar 1 $v1 var
... |
http://rosettacode.org/wiki/Enforced_immutability | Enforced immutability | Task
Demonstrate any means your language has to prevent the modification of values, or to create objects that cannot be modified after they have been created.
| #UNIX_Shell | UNIX Shell | PIE=APPLE
readonly PIE |
http://rosettacode.org/wiki/Enforced_immutability | Enforced immutability | Task
Demonstrate any means your language has to prevent the modification of values, or to create objects that cannot be modified after they have been created.
| #XPL0 | XPL0 | define Pi=3.14;
Pi:= 3.15; \causes a compile error: statement starting with a constant
|
http://rosettacode.org/wiki/Entropy | Entropy | Task
Calculate the Shannon entropy H of a given input string.
Given the discrete random variable
X
{\displaystyle X}
that is a string of
N
{\displaystyle N}
"symbols" (total characters) consisting of
n
{\displaystyle n}
different characters (n=2 for binary), the Shannon entropy of X in bit... | #Delphi | Delphi |
program Entropytest;
uses
StrUtils,
Math;
type
FArray = array of CARDINAL;
var
strng: string = '1223334444';
// list unique characters in a string
function uniquechars(str: string): string;
var
n: CARDINAL;
begin
Result := '';
for n := 1 to length(str) do
if (PosEx(str[n], str, n) > 0) and (... |
http://rosettacode.org/wiki/Ethiopian_multiplication | Ethiopian multiplication | Ethiopian multiplication is a method of multiplying integers using only addition, doubling, and halving.
Method:
Take two numbers to be multiplied and write them down at the top of two columns.
In the left-hand column repeatedly halve the last number, discarding any remainders, and write the result below the last ... | #Common_Lisp | Common Lisp | (defun ethiopian-multiply (l r)
(flet ((halve (n) (floor n 2))
(double (n) (* n 2))
(even-p (n) (zerop (mod n 2))))
(do ((product 0 (if (even-p l) product (+ product r)))
(l l (halve l))
(r r (double r)))
((zerop l) product)))) |
http://rosettacode.org/wiki/Equilibrium_index | Equilibrium index | An equilibrium index of a sequence is an index into the sequence such that the sum of elements at lower indices is equal to the sum of elements at higher indices.
For example, in a sequence
A
{\displaystyle A}
:
A
0
=
−
7
{\displaystyle A_{0}=-7}
A
1
=
1
{\displaystyle A_{1}=1}
... | #Liberty_BASIC | Liberty BASIC |
a(0)=-7
a(1)=1
a(2)=5
a(3)=2
a(4)=-4
a(5)=3
a(6)=0
print "EQ Indices are ";EQindex$("a",0,6)
wait
function EQindex$(b$,mini,maxi)
if mini>=maxi then exit function
sum=0
for i = mini to maxi
sum=sum+eval(b$;"(";i;")")
next
sumA=0:sumB=sum
for i = mini to maxi
sumB = sumB -... |
http://rosettacode.org/wiki/Environment_variables | Environment variables | Task
Show how to get one of your process's environment variables.
The available variables vary by system; some of the common ones available on Unix include:
PATH
HOME
USER
| #Pike | Pike | write("%s\n", getenv("SHELL")); |
http://rosettacode.org/wiki/Environment_variables | Environment variables | Task
Show how to get one of your process's environment variables.
The available variables vary by system; some of the common ones available on Unix include:
PATH
HOME
USER
| #PowerShell | PowerShell | $Env:Path |
http://rosettacode.org/wiki/Environment_variables | Environment variables | Task
Show how to get one of your process's environment variables.
The available variables vary by system; some of the common ones available on Unix include:
PATH
HOME
USER
| #Prolog | Prolog | ?- getenv('TEMP', Temp).
|
http://rosettacode.org/wiki/Environment_variables | Environment variables | Task
Show how to get one of your process's environment variables.
The available variables vary by system; some of the common ones available on Unix include:
PATH
HOME
USER
| #PureBasic | PureBasic | GetEnvironmentVariable("Name") |
http://rosettacode.org/wiki/Euler%27s_sum_of_powers_conjecture | Euler's sum of powers conjecture | There is a conjecture in mathematics that held for over two hundred years before it was disproved by the finding of a counterexample in 1966 by Lander and Parkin.
Euler's (disproved) sum of powers conjecture
At least k positive kth powers are required to sum to a kth power,
except for the trivial case... | #Java | Java | public class eulerSopConjecture
{
static final int MAX_NUMBER = 250;
public static void main( String[] args )
{
boolean found = false;
long[] fifth = new long[ MAX_NUMBER ];
for( int i = 1; i <= MAX_NUMBER; i ++ )
{
long i2 = i * i;
fifth[ i... |
http://rosettacode.org/wiki/Factorial | Factorial | Definitions
The factorial of 0 (zero) is defined as being 1 (unity).
The Factorial Function of a positive integer, n, is defined as the product of the sequence:
n, n-1, n-2, ... 1
Task
Write a function to return the factorial of a number.
Solutions can be iterat... | #OCaml | OCaml | let rec factorial n =
if n <= 0 then 1
else n * factorial (n-1) |
http://rosettacode.org/wiki/Even_or_odd | Even or odd | Task
Test whether an integer is even or odd.
There is more than one way to solve this task:
Use the even and odd predicates, if the language provides them.
Check the least significant digit. With binary integers, i bitwise-and 1 equals 0 iff i is even, or equals 1 iff i is odd.
Divide i by 2. The remainder equals... | #DCL | DCL | $! in DCL, for integers, the least significant bit determines the logical value, where 1 is true and 0 is false
$
$ i = -5
$ loop1:
$ if i then $ write sys$output i, " is odd"
$ if .not. i then $ write sys$output i, " is even"
$ i = i + 1
$ if i .le. 6 then $ goto loop1 |
http://rosettacode.org/wiki/Euler_method | Euler method | Euler's method numerically approximates solutions of first-order ordinary differential equations (ODEs) with a given initial value. It is an explicit method for solving initial value problems (IVPs), as described in the wikipedia page.
The ODE has to be provided in the following form:
d
y
(
t
)
d
t
=
f... | #VBA | VBA | Private Sub ivp_euler(f As String, y As Double, step As Integer, end_t As Integer)
Dim t As Integer
Debug.Print " Step "; step; ": ",
Do While t <= end_t
If t Mod 10 = 0 Then Debug.Print Format(y, "0.000"),
y = y + step * Application.Run(f, y)
t = t + step
Loop
Debug.Print
En... |
http://rosettacode.org/wiki/Evaluate_binomial_coefficients | Evaluate binomial coefficients | This programming task, is to calculate ANY binomial coefficient.
However, it has to be able to output
(
5
3
)
{\displaystyle {\binom {5}{3}}}
, which is 10.
This formula is recommended:
(
n
k
)
=
n
!
(
n
−
k
)
!
k
!
=
n
(
n
−
1
)
(
n
−
2
)
…
(
n
−
k
+
1
)
k
(
k
−
1... | #Maple | Maple | convert(binomial(n,k),factorial);
binomial(5,3); |
http://rosettacode.org/wiki/Evaluate_binomial_coefficients | Evaluate binomial coefficients | This programming task, is to calculate ANY binomial coefficient.
However, it has to be able to output
(
5
3
)
{\displaystyle {\binom {5}{3}}}
, which is 10.
This formula is recommended:
(
n
k
)
=
n
!
(
n
−
k
)
!
k
!
=
n
(
n
−
1
)
(
n
−
2
)
…
(
n
−
k
+
1
)
k
(
k
−
1... | #Mathematica_.2F_Wolfram_Language | Mathematica / Wolfram Language | (Local) In[1]:= Binomial[5,3]
(Local) Out[1]= 10 |
http://rosettacode.org/wiki/Emirp_primes | Emirp primes | An emirp (prime spelled backwards) are primes that when reversed (in their decimal representation) are a different prime.
(This rules out palindromic primes.)
Task
show the first twenty emirps
show all emirps between 7,700 and 8,000
show the 10,000th emirp
In each list, the numbe... | #Common_Lisp | Common Lisp | (defun primep (n)
"Is N prime?"
(and (> n 1)
(or (= n 2) (oddp n))
(loop for i from 3 to (isqrt n) by 2
never (zerop (rem n i)))))
(defun reverse-digits (n)
(labels ((next (n v)
(if (zerop n) v
(multiple-value-bind (q r)
(truncate n 10)
... |
http://rosettacode.org/wiki/Elliptic_curve_arithmetic | Elliptic curve arithmetic | Elliptic curves are sometimes used in cryptography as a way to perform digital signatures.
The purpose of this task is to implement a simplified (without modular arithmetic) version of the elliptic curve arithmetic which is required by the elliptic curve DSA protocol.
In a nutshell, an elliptic curve is a... | #PicoLisp | PicoLisp | (scl 16)
(load "@lib/math.l")
(setq *B 7)
(de from_y (Y)
(let
(A (* 1.0 (- (* Y Y) *B))
B (pow (abs A) (*/ 1.0 1.0 3.0)) )
(list
(if (gt0 A) B (- B))
(* Y 1.0) ) ) )
(de prn (P)
(if (is_zero P)
"Zero"
(pack
(round (car P) 3)
" "
(round ... |
http://rosettacode.org/wiki/Elliptic_curve_arithmetic | Elliptic curve arithmetic | Elliptic curves are sometimes used in cryptography as a way to perform digital signatures.
The purpose of this task is to implement a simplified (without modular arithmetic) version of the elliptic curve arithmetic which is required by the elliptic curve DSA protocol.
In a nutshell, an elliptic curve is a... | #Python | Python | #!/usr/bin/env python3
class Point:
b = 7
def __init__(self, x=float('inf'), y=float('inf')):
self.x = x
self.y = y
def copy(self):
return Point(self.x, self.y)
def is_zero(self):
return self.x > 1e20 or self.x < -1e20
def neg(self):
return Point(self.... |
http://rosettacode.org/wiki/Enumerations | Enumerations | Task
Create an enumeration of constants with and without explicit values.
| #OCaml | OCaml | type fruit =
| Apple
| Banana
| Cherry |
http://rosettacode.org/wiki/Enumerations | Enumerations | Task
Create an enumeration of constants with and without explicit values.
| #Oforth | Oforth | [ $apple, $banana, $cherry ] const: Fruits |
http://rosettacode.org/wiki/Enumerations | Enumerations | Task
Create an enumeration of constants with and without explicit values.
| #Ol | Ol |
(define fruits '{
apple 0
banana 1
cherry 2})
; or
(define fruits {
'apple 0
'banana 1
'cherry 2})
; getting enumeration value:
(print (get fruits 'apple -1)) ; ==> 0
; or simply
(print (fruits 'apple)) ; ==> 0
; or simply with default (for non existent enumeration key) value
(print (frui... |
http://rosettacode.org/wiki/Elementary_cellular_automaton/Random_Number_Generator | Elementary cellular automaton/Random Number Generator | Rule 30 is considered to be chaotic enough to generate good pseudo-random numbers. As a matter of fact, rule 30 is used by the Mathematica software for its default random number generator.
Steven Wolfram's recommendation for random number generation from rule 30 consists in extracting successive bits in a fixed positi... | #zkl | zkl | fcn rule(n){ n=n.toString(2); "00000000"[n.len() - 8,*] + n }
fcn applyRule(rule,cells){
cells=String(cells[-1],cells,cells[0]); // wrap edges
(cells.len() - 2).pump(String,'wrap(n){ rule[7 - cells[n,3].toInt(2)] })
}
fcn rand30{
var r30=rule(30), cells="0"*63 + 1; // 64 bits (8 bytes), arbitrary
n:=0;
... |
http://rosettacode.org/wiki/Empty_string | Empty string | Languages may have features for dealing specifically with empty strings
(those containing no characters).
Task
Demonstrate how to assign an empty string to a variable.
Demonstrate how to check that a string is empty.
Demonstrate how to check that a string is not empty.
Other tasks related to string oper... | #Bracmat | Bracmat | ( :?a
& (b=)
& abra:?c
& (d=cadabra)
& !a: { a is empty string }
& !b: { b is also empty string }
& !c:~ { c is not an empty string }
& !d:~ { neither is d an empty string }
)
|
http://rosettacode.org/wiki/Empty_string | Empty string | Languages may have features for dealing specifically with empty strings
(those containing no characters).
Task
Demonstrate how to assign an empty string to a variable.
Demonstrate how to check that a string is empty.
Demonstrate how to check that a string is not empty.
Other tasks related to string oper... | #Burlesque | Burlesque |
blsq ) ""
""
blsq ) ""nu
1
blsq ) "a"nu
0
|
http://rosettacode.org/wiki/Empty_directory | Empty directory | Starting with a path to some directory, determine whether the directory is empty.
An empty directory contains no files nor subdirectories.
With Unix or Windows systems, every directory contains an entry for “.” and almost every directory contains “..” (except for a root directory); an empty directory contains no other... | #Julia | Julia | # v0.6.0
isemptydir(dir::AbstractString) = isempty(readdir(dir))
@show isemptydir(".")
@show isemptydir("/home")
|
http://rosettacode.org/wiki/Empty_directory | Empty directory | Starting with a path to some directory, determine whether the directory is empty.
An empty directory contains no files nor subdirectories.
With Unix or Windows systems, every directory contains an entry for “.” and almost every directory contains “..” (except for a root directory); an empty directory contains no other... | #Kotlin | Kotlin | // version 1.1.4
import java.io.File
fun main(args: Array<String>) {
val dirPath = "docs" // or whatever
val isEmpty = (File(dirPath).list().isEmpty())
println("$dirPath is ${if (isEmpty) "empty" else "not empty"}")
} |
http://rosettacode.org/wiki/Empty_directory | Empty directory | Starting with a path to some directory, determine whether the directory is empty.
An empty directory contains no files nor subdirectories.
With Unix or Windows systems, every directory contains an entry for “.” and almost every directory contains “..” (except for a root directory); an empty directory contains no other... | #Lasso | Lasso | dir('has_content') -> isEmpty
'<br />'
dir('no_content') -> isEmpty |
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