数组是
`Array
(

[0] => Array
    (
        [id] => 1
        [pid] => 0
        [name] => 安徽省
        [son] => Array
            (
                [0] => Array
                    (
                        [id] => 3
                        [pid] => 1
                        [name] => 合肥市
                        [son] => Array
                            (
                                [0] => Array
                                    (
                                        [id] => 4
                                        [pid] => 3
                                        [name] => 长丰县
                                    )

                            )

                    )

                [1] => Array
                    (
                        [id] => 5
                        [pid] => 1
                        [name] => 安庆市
                    )

            )

    )

[1] => Array
    (
        [id] => 2
        [pid] => 0
        [name] => 浙江省
    )

)`

然后我把他们列出来 很傻瓜的写法 只能输出三级循环

foreach(上面的数组 as $row) 

 {   echo $row['id']; 

     echo $row['name']; 


  if(isset($row['son'])){

     foreach($row['son'] as $k => $v){ 

         echo $v['id']; 

         echo $v['name']; 

       
         if(isset($v['son'])){
               foreach($v['son'] as $m => $n){ 

                 echo $n['id']; 

                 echo $n['name']; 

               } 
     } 





     } 

   }
 }

这样写效率不好吧?
如何简化写法？或者无限循环。。。