PHP Array randomization

I’m a bit perplexed why you can sort an array with keys in PHP and you can randomize an array with no keys, but you cannot randomize an array with keys. Weird…

If you have to randomize an array with keys, here is a way to do it. Would have been nice to have been able to simply say:

shuffle($arrayWithKeys);

but thats not to be as you would lose the keys.

So what you need to do is:

//Make an array without keys of the keys of your associative array
$keys = array_keys($arrayWithKeys);

//Shuffle the keys up
shuffle($keys);

//New array which is the one you would use or return
$newArrayWithKeys = array(); 

foreach($keys as $k) {

    //The array items would be packed into the new array in the order that it was shuffled.
    $newArrayWithKeys[] = $arrayWithKeys[$key];

}

Thanks to Sajith for the tip!

2 Comments to "PHP Array randomization"

• Chris M said: On 10/18/2007 at 9:36 pm

  I love this sentence: “you can randomize an array with no keys, but you cannot randomize an array with keys.” - had to read that a couple times

• Stii said: On 10/19/2007 at 6:18 am

  @Chris: yeah you’re right! Quite a tongue twister isn’t it!

Spit it out!

Filed in: PHP, Programming by: Stii