004+
005+ Warning: array_diff_key() expects parameter 2 to be a valid callback, array must have exactly two members in %s/array_diff_key_variation5.php on line 15
006+ NULL
007+
008+ Warning: array_diff_key() expects parameter 2 to be a valid callback, array must have exactly two members in %s/array_diff_key_variation5.php on line 16
009+ NULL
004- array(2) {
005- [20]=>
006- string(2) "20"
007- [-20]=>
008- string(3) "-20"
009- }
010- array(0) {
011- }