usort

Hi, I'm trying sort an array. It has entries like this: file_1.ext file_2.ext file_3.ext file_10.ext file_40.ext and so on. I want to sort them alphabetically first and then by the numbers. If I sort them normally I get them like this: file_1.ext file_10.ext file_2.ext file_3.ext file_40.ext What I'm thinking of is like this: function mycmp($a, $b) { if ($a == $b) {

       		return 0;

} $a_n = preg_match("/\D+(\d+)\D+/", $a, $a_out); $b_n = preg_match("/\D+(\d+)\D+/", $b, $b_out); return ($a_n[1] < $b_n[1]) ? -1 : 1; } But it doesn't work the way it should. Any suggestions? So this is a the callback-function for the usort funtion. Shmuel.