<meta http-equiv="Content-Type" content="text/html;charset=UTF-8">

 <?php

 $tree=array(

     array('id'=>1,'name'=>'安徽','pid'=>'0'),

     array('id'=>2,'name'=>'北京','pid'=>'0'),

     array('id'=>3,'name'=>'山东','pid'=>'0'),

     array('id'=>4,'name'=>'昭阳区','pid'=>'2'),

     array('id'=>5,'name'=>'合肥市','pid'=>'1'),

     array('id'=>6,'name'=>'蜀山区','pid'=>'5'),

     array('id'=>7,'name'=>'烟台市','pid'=>'3'),

     );

 /**

  * @param $data array

  * @param $pid parent_id

  * @param $level

  * @author tian

  */

 function tree($data,$pid=0,$level=1){

     static $arr=array();

     foreach($data as $v){

         if($v['pid']==$pid){

             $v['level']=$level;

             $arr[]=$v;

             tree($data,$v['id'],$level+1);

         }

     }

 return $arr;

 }

 $list=tree($tree,0,1);

 var_dump($list);

  ?>