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Programming-Idioms

# 10 Shuffle a list
New implementation

Be concise.

Be useful.

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Please try to avoid dependencies to third-party libraries and frameworks.

Other implementations 
#include <stdlib.h>
#include <time.h>
srand(time(NULL));
for (int i = 0; i < N-1; ++i)
{
    int j = rand() % (N-i) + i;
    int temp = x[i];
    x[i] = x[j];
    x[j] = temp;
}
(shuffle collection)
#include <algorithm>
#include <vector>
std::random_shuffle(my_collection.begin(), my_collection.end());
using System;
using System.Collections.Generic;
private static Random rng = new Random();  

public static void Shuffle<T>(this IList<T> list)  
{  
    int n = list.Count;  
    while (n > 1) {  
        n--;  
        int k = rng.Next(n + 1);  
        T value = list[k];  
        list[k] = list[n];  
        list[n] = value;  
    }  
}
import std.random;
randomShuffle(x);
var shuffled = x.toList()..shuffle();
x.shuffle();
y = Enum.shuffle x
[Y||{_,Y} <- lists:sort([ {rand:uniform(), N} || N <- X])].
module M_shuffle
contains
function scramble( number_of_values ) result(array)
   integer,intent(in)    :: number_of_values
   integer,allocatable   :: array(:)
   array=[(i,i=1,number_of_values)]
   n=1; m=number_of_values
   do k=1,2
    do i=1,m
     call random_number(u)
     j = n + FLOOR((m+1-n)*u)
     itemp=array(j); array(j)=array(i); array(i)=itemp
    enddo
   enddo
end function scramble
end module M_shuffle
 :
use M_shuffle, only : scramble
newlist=list(scramble(size(list))

import "math/rand"
rand.Shuffle(len(x), func(i, j int) {
	x[i], x[j] = x[j], x[i]
})
import "math/rand"
for i := len(x) - 1; i > 0; i-- {
	j := rand.Intn(i + 1)
	x[i], x[j] = x[j], x[i]
}
import "math/rand"
for i := range x {
	j := rand.Intn(i + 1)
	x[i], x[j] = x[j], x[i]
}
import "math/rand"
y := make([]T, len(x))
perm := rand.Perm(len(x))
for i, v := range perm {
	y[v] = x[i]
}
x.shuffle()
shuffle x = if length x < 2 then return x else do
	i <- System.Random.randomRIO (0, length(x)-1)
	r <- shuffle (take i x ++ drop (i+1) x)
	return (x!!i : r)

for (var i = x.length - 1; i > 0; i--) {
    var j = Math.floor(Math.random() * (i + 1));
    var temp = x[j];
    x[j] = x[i];
    x[i] = temp;
}
import java.util.Collections;
Collections.shuffle(x);
mutableList.shuffle()
val newList = list.shuffled()
function(list)
	for i = #list, 2, -1 do
		local j = math.random(i)
		list[i], list[j] = list[j], list[i]
	end
end

shuffled = {}
for i, v in ipairs(x) do
	local pos = math.random(1, #shuffled+1)
	table.insert(shuffled, pos, v)
end
@import GameplayKit;
x.shuffledArray
shuffle($x);
var Iter,rr: integer; 
[...]
  for Iter := 0 to high(List) do
    begin
      rr := random(high(List))+1;
      tmp := List[Iter];
      List[Iter] := List[rr];
      List[rr] := tmp;
    end;

use List::Util 'shuffle';
@shuffled = shuffle('a', 'b', 'c', 'd', 'e', 'f');
from random import shuffle
shuffle(x)
import random
random.shuffle(list)
x.shuffle
shuffled_list = x.shuffle
use rand::seq::SliceRandom;
use rand::thread_rng;
let mut rng = thread_rng();
x.shuffle(&mut rng);
extern crate rand;
use rand::{Rng, StdRng};
let mut rng = StdRng::new().unwrap();
rng.shuffle(&mut x);
import scala.util.Random
val items = List(1, 2, 3, 4, 5)
val shuffledItems = Random.shuffle(items)
(shuffle x)
(define shuffle
  (lambda (list)
    (if (< (length list) 2) 
        list
        (let ((item (list-ref list (random (length list)))))
          (cons item (shuffle (remove item list)))))))
Function Shuffle(Of T)(collection As IEnumerable(Of T)) As List(Of T)
    Dim r As Random = New Random()
    Shuffle = collection.OrderBy(Function(a) r.Next()).ToList()
End Function

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