PHP 按二维数组的键值排序

/**
     * 按二维数组的键值排序
     * @param unknown $array 二维数组
     * @param unknown $key   二维数组的键值
     * @param string $order  升序/降序
     * @return multitype:unknown  返回排序后的数组
     */
    public static function arr_sort_in_key($array, $key, $order = "asc")
    {
        $arr_nums = $arr = array();

        foreach ($array as $k => $v)
        {
            $arr_nums[$k] = $v[$key];
        }

        if($order=='asc')
        {
            asort($arr_nums);
        }
        else
        {
            arsort($arr_nums);
        }

        foreach($arr_nums as $k=>$v)
        {
            $arr[] = $array[$k];
        }

        return $arr;

    }