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... callablekey_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 a 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 &return.callbacksort; &callback.cmp; &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