array_diff_uassoc Computes the difference of arrays with additional index check which is performed by a user supplied callback function &reftitle.description; arrayarray_diff_uassoc arrayarray1 arrayarray2 array... callbackkey_compare_func Compares array1 against array2 and returns the difference. Unlike array_diff the array keys are used in the comparison. Unlike array_diff_assoc an user supplied callback function is used for the indices comparison, not internal function. &reftitle.parameters; array1 The array to compare from array2 An array to compare against ... More arrays to compare against key_compare_func callback function to use. The callback function must return an integer less than, equal to, or greater than zero if the first argument is considered to be respectively less than, equal to, or greater than the second. &reftitle.returnvalues; Returns an array containing all the entries from array1 that are not present in any of the other arrays. &reftitle.examples; The "a" => "green" pair is present in both arrays and thus it is not in the output from the function. Unlike this, the pair 0 => "red" is in the output because in the second argument "red" has key which is 1. $b)? 1:-1; } $array1 = array("a" => "green", "b" => "brown", "c" => "blue", "red"); $array2 = array("a" => "green", "yellow", "red"); $result = array_diff_uassoc($array1, $array2, "key_compare_func"); print_r($result); ?> ]]> &example.outputs; brown [c] => blue [0] => red ) ]]> The equality of 2 indices is checked by the user supplied callback function. &reftitle.notes; This function only checks one dimension of a n-dimensional array. Of course you can check deeper dimensions by using, for example, array_diff_uassoc($array1[0], $array2[0], "key_compare_func");. &reftitle.seealso; array_diff array_diff_assoc array_udiff array_udiff_assoc array_udiff_uassoc array_intersect array_intersect_assoc array_uintersect array_uintersect_assoc array_uintersect_uassoc