/**

     * 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;

    }