do you know better performance solution for sorting array in array in array?

Question

I want to sort the array based on their sku alphabetically and I wrote this program with three foraeach loop, I think I did not write it as the best solution, do you know any other better?what is your idea about it?

$array[] =  array('data' => array('entity_id' => 3446,'sku' => 'A'));
$array[] =  array('data' => array('entity_id' => 3546,'sku' => 'D'));
$array[] =  array('data' => array('entity_id' => 7446,'sku' => 'C'));
$array[] =  array('data' => array('entity_id' => 2446,'sku' => 'B'));
$array[] =  array('data' => array('entity_id' => 7446,'sku' => 'E'));
$array[] =  array('data' => array('entity_id' => 9446,'sku' => 'F'));

foreach ($array as $key => $data) {
    foreach ($data as $k=> $v)
        {
    $newarray[$key]  = $v['sku'];
        }
            }

asort($newarray);

foreach ( $newarray as $k=>$v)
$keys[]=$k;

$result=array();
foreach($keys as $k=>$v) {
    $result[$k] = $array[$v];
}

Answer 1

Assuming you want to sort just the outer array, all you need is a custom sort function:

usort($array, "sort_by_sku");

function sort_by_sku($a, $b) {
    return strcmp($a["data"]["sku"], $b["data"]["sku"]);
}