Question

How to randomize array in JavaScript

Answer 1

function randomizeArray(array) 
{
  var index = array.length, randomIndex, tmp;

  while (index) 
  {
    randomIndex = Math.floor(Math.random() * index);
    index -= 1;

    tmp = array[index];
    array[index] = array[randomIndex];
    array[randomIndex] = tmp;
  }

  return array;
}

var array = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
array = randomizeArray(array);
document.write(array);
   
 
/*
run:
 
9,6,7,0,2,4,5,1,3,8 
 
*/

 

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Answer 2

function randomizeArray(array) 
{
  var randomIndex, tmp;
 
  for (var index = array.length - 1; index > 0; index--) 
  {
        randomIndex = Math.floor(Math.random() * (index + 1));
         
        tmp = array[index];
        array[index] = array[randomIndex];
        array[randomIndex] = tmp;
  }
 
  return array;
}
 

var array = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
array = randomizeArray(array);
document.write(array);
   
 
/*
run:
 
5,6,9,0,3,1,7,2,8,4 
 
*/

 

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