根据某个key给二维数组分组

    /**
     * 根据某个key给二维数组分组
     */
    private  function array_group_by($arr, $key) {
        $grouped = [];
        foreach ($arr as $value) {
            $grouped[$value[$key]][] = $value;
        }
        if (func_num_args() > 2) {
            $args = func_get_args();
            foreach ($grouped as $key => $value) {
                $parms = array_merge([$value], array_slice($args, 2, func_num_args()));
                $grouped[$key] = call_user_func_array('array_group_by', $parms);
            }
        }
        return $grouped;
    }