How to generate function random array

MDN
#1

I need to do a function that reandomize all of the positions of an array.

#3

Hi good morning, this is an easy way to do it:

function randomize(array){
var i,j,k;
for (i = array.length; i; i–) {
j = Math.floor(Math.random() * i);
k = array[i - 1];
array[i - 1] = array[j];
array[j] = k;
}
return array;
};

Let me know any question.

1 Like
#4

Hello @DeveLop and @drektmr and welcome to the community :wave:

For whoever is wondering: This is called the Fisher–Yates shuffle.

Thanks for the example @drektmr. Due to using blockquotes the forum transformed your i-- into i– which gives a syntax error.
This would be a ready to copy version of your function with modernized JS:

function randomize(arr){
  let i, j;
  for (i = arr.length; i; i--) {
    j = Math.floor(Math.random() * i);
    [arr[i - 1], arr[j]] = [arr[j], arr[i - 1]];
  }
  return arr;
}

It uses Destructuring to swap the variables.

I hope that helps!

Have a nice day both of you!
Michael

1 Like