Sort array by object property in PHP?

Question

If I have an object as such:

class Person {
  var $age;
  function __construct($age) {
    $this->age = $age;
  }
}

and I have any array

Answer 1

I just coded this. It should be faster than usort as it does not rely on numerous function calls.

function sortByProp($array, $propName, $reverse = false)
{
    $sorted = [];

    foreach ($array as $item)
    {
        $sorted[$item->$propName][] = $item;
    }

    if ($reverse) krsort($sorted); else ksort($sorted);
    $result = [];

    foreach ($sorted as $subArray) foreach ($subArray as $item)
    {
        $result[] = $item;
    }

    return $result;
}

Usage:

$sorted = sortByProp($people, 'age');

Oh, and it uses ksort but it works even if many $people are of the same $age.