Sort multidimensional array

Snipplr-63256.txt

<?php
$transactions = array(
0 => array('date'=>1324235252, 'day'=>'monday'),
1 => array('date'=>1326516552, 'day'=>'tuesday'),
2 => array('date'=>1333453235, 'day'=>'wednesday')
)

function sortByOrder($a, $b) {
    return $b['date'] - $a['date'];
}

usort($transactions, 'sortByOrder');