PHP retrieve array of items from a multidimensional array without looping?

Question

I have a large array of arrays and each of these sub-arrays has an ID and some other info. Is there a way to access an array of just the ID's without using a loop?

Sort of like

$array[ALLOFTHEITEMS][Id]; 

I want to eventually compare these ID's to another flat array of ID's. I would usually do a for loop and then just add the id of each item to a new array and then compare them. But is there a faster way?

Answer 1

Not sure if its faster then foreach as I've never benchmarked it but an alternative to foreach would be:

php 5.3

$ids = array_map(function($data) { return $data['id']; }, $array);

php < 5.3

function reduceToIds($data) {
    return $data['id'];
}

$ids = array_map('reduceToIds', $array);

I normally use the foreach approach myself though.