if (in_array('a', $array_under_test) || in_array('b', $array_under_test)) { // Success! }
$uniqueKeys = array_unique($list[0]) foreach ($uniqueKeys as $uniqueKey) { $v = array_keys($list[0], $uniqueKey); if (count($v) > 1) { foreach ($v as $key) { // Work with $list[0][$key] } } }