array_udiff Computes the difference of arrays by using a callback function for data comparison &reftitle.description; arrayarray_udiff arrayarray1 arrayarray2 array ... callabledata_compare_func Computes the difference of arrays by using a callback function for data comparison. This is unlike array_diff which uses an internal function for comparing the data. &reftitle.parameters; array1 The first array. array2 The second array. data_compare_func The callback comparison function. &return.callbacksort; &callback.cmp; &reftitle.returnvalues; Returns an array containing all the values of array1 that are not present in any of the other arguments. &reftitle.examples; <function>array_udiff</function> example priv_member = $val; } static function comp_func_cr($a, $b) { if ($a->priv_member === $b->priv_member) return 0; return ($a->priv_member > $b->priv_member)? 1:-1; } } $a = array("0.1" => new cr(9), "0.5" => new cr(12), 0 => new cr(23), 1=> new cr(4), 2 => new cr(-15),); $b = array("0.2" => new cr(9), "0.5" => new cr(22), 0 => new cr(3), 1=> new cr(4), 2 => new cr(-15),); $result = array_udiff($a, $b, array("cr", "comp_func_cr")); print_r($result); ?> ]]> &example.outputs; cr Object ( [priv_member:private] => 12 ) [0] => cr Object ( [priv_member:private] => 23 ) ) ]]> &reftitle.notes; Please note that this function only checks one dimension of a n-dimensional array. Of course you can check deeper dimensions by using array_udiff($array1[0], $array2[0], "data_compare_func");. &reftitle.seealso; array_diff array_diff_assoc array_diff_uassoc array_udiff_assoc array_udiff_uassoc array_intersect array_intersect_assoc array_uintersect array_uintersect_assoc array_uintersect_uassoc