--TEST-- Test array_intersect_ukey() function : usage variation - Passing class/object methods to callback --FILE-- 1, 'red' => 2, 'green' => 3, 'purple' => 4); $array2 = array('green' => 5, 'blue' => 6, 'yellow' => 7, 'cyan' => 8); class MyClass { static function static_compare_func($key1, $key2) { return strcasecmp($key1, $key2); } public function class_compare_func($key1, $key2) { return strcasecmp($key1, $key2); } } echo "\n-- Testing array_intersect_ukey() function using class with static method as callback --\n"; var_dump( array_intersect_ukey($array1, $array2, array('MyClass','static_compare_func')) ); var_dump( array_intersect_ukey($array1, $array2, 'MyClass::static_compare_func') ); echo "\n-- Testing array_intersect_uassoc() function using class with regular method as callback --\n"; $obj = new MyClass(); var_dump( array_intersect_ukey($array1, $array2, array($obj,'class_compare_func')) ); ?> ===DONE=== --EXPECTF-- *** Testing array_intersect_ukey() : usage variation *** -- Testing array_intersect_ukey() function using class with static method as callback -- array(2) { ["blue"]=> int(1) ["green"]=> int(3) } array(2) { ["blue"]=> int(1) ["green"]=> int(3) } -- Testing array_intersect_uassoc() function using class with regular method as callback -- array(2) { ["blue"]=> int(1) ["green"]=> int(3) } ===DONE===