Sort Multidimensional Array by Sub-Array Key’s Value (http://www.bitrepository.com/php-sort-multidimensional-array-sub-array-key-value.html)

example.php

$array = array(
    array(
        'name' => 'Lorem Ipsum',
        'position' => 4
    ),
     
    array(
        'name' => 'Just a title',
        'position' => 3
    ),
     
    array(
        'name' => 'Dummy title here',
        'position' => 5
    )   
);
 
$sort = new SortMdArray;
$sort->sortByKey($array);
 
echo '<pre>'; print_r($array); echo '</pre>';

$sort = new SortMdArray;
$sort->sort_order = 'desc'; // from highest to lowest
$sort->sort_key = 'quantity';
$sort->sortByKey($array);

SortMdArray.php

class SortMdArray {
    public $sort_order = 'asc'; // default
    public $sort_key = 'position'; // default
     
    public function sortByKey(&$array) {       
        usort($array, array(__CLASS__, 'sortByKeyCallback'));     
    }
     
    function sortByKeyCallback($a, $b) {
        if($this->sort_order == 'asc') {
            $return = $a[$this->sort_key] - $b[$this->sort_key];
        } else if($this->sort_order == 'desc') {
            $return = $b[$this->sort_key] - $a[$this->sort_key];
        }
        return $return;
    } 
}