uksort Sort an array by keys using a user-defined comparison function voiduksort arrayarray callbackcmp_function This function will sort the keys of an array using a user-supplied comparison function. If the array you wish to sort needs to be sorted by some non-trivial criteria, you should use this function. $b) ? -1 : 1; } $a = array (4 => "four", 3 => "three", 20 => "twenty", 10 => "ten"); uksort ($a, "cmp"); while (list ($key, $value) = each ($a)) { echo "$key: $value\n"; } ?> ]]> This example would display: See also usort, uasort, sort, asort, arsort, ksort, natsort, and rsort.