如何按日期按升序排列此数组？

Question

this is my array

[comment] => Array
        (
            [0] => Array
                (
                    [mem_id] => 51
                    [comment] => nice...
                    [profilenam] => xyz
                    [photo_thumb] => photos/81951b37ad01c4aa65662956f178214eth.jpeg
                    [date] => 1307975661
                )

            [1] => Array
                (
                    [mem_id] => 329
                    [comment] => nice...
                    [profilenam] => abc
                    [photo_thumb] => photos/f841eab12f5a24ce12b984904760c05fth.jpeg
                    [date] => 1308043486
                )

        )

actually i wanted to arrange in ascending order by date , i used asort() but didn't work

Answer 1

usort($ar['comment'], function($v1, $v2) {
    return $v1['date'] - $v2['date'];
});

In php<5.3, use create_function instead of the anonymous function notation.