Example of sorting a php two-dimensional array by a specified key value

/**
* PHP two-dimensional array is sorted by the specified key value key
* by bbs.it-home.org
*/
function array_sort($array, $key){
if(is_array($array)){
$key_array = null;
$new_array = null;
for( $i = 0; $i < count( $array ); $i++ ){
$key_array[$array[$i][$key]] = $i;
}
ksort($key_array);
$j = 0;
foreach($key_array as $k => $v){
$new_array[$j] = $array[$v];
$j++;
}
unset($key_array);
return $new_array;
}else{
return $array;
}
}