php二维数组按照键值排序的方法

    //按照传入数组中的num倒序
    public function numdesc($array,$key="num",$order="desc"){
        $arr_nums=$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){
            $arr[$k]=$array[$k];
        }
        return $arr;
        }