Randomize Array – Shuffle an array in Flash

After I’ve post solution for shuffling an array with Array.sort method which purspose was to just show what a sort function can be used for I am now posting solution which is best for doing a shuffle of an array. There were few discussions about it on the web.

I’ve made a little test to demonstrate speed of testing

There are 4 methods
First one is Array.sort, second is using splice and last two are basiclly the same, one beign prototype for array and second is plain function which returns an array.

Speed test returned following results (could vary a little bit but not spectacular):

For 1500 elements
Sort – 2216 ms
Splice – 8300 ms
Prototype – 16 ms
Return Function -15 ms

You can take test file here

Prototype function and return function code is :

Array.prototype.mixElements = function() {
var _length:Number = this.length, rn:Number, it:Number, el:Object;
for (it = 0; it<_length; it++) {
el = this[it];
this[it] = this[rn = random(_length)];
this[rn] = el;
}
}

function mixArray(array:Array):Array {
var _length:Number = array.length, mixed:Array = array.slice(), rn:Number, it:Number, el:Object;
for (it = 0; it<_length; it++) {
el = mixed[it];
mixed[it] = mixed[rn = random(_length)];
mixed[rn] = el;
}
return mixed;
}

Code is only for AS2 but it can be easily turned into AS3 code