tarsana / functional

        $index = 0;

        $keys = array_keys($list);

        $length = count($keys);

        while ($index < $length) {

            if (_equals($item, $list[$keys[$index]]))

                return $keys[$index];

            $index ++;

        }

        return -1;

    });

    return _apply($indexOf, func_get_args());

        $list = (array) $list;

        $keys = array_keys($list);

        $index = count($list) - 1;

        while ($index >= 0) {

            if (_equals($list[$keys[$index]], $item))

                return $keys[$index];

            $index --;

        }

        return -1;

    });

    return _apply($lastIndexOf, func_get_args());