php递归实现无限级分类

<?php
$area = array(

array('id'=>1,'name'=>'河北','parent'=>0),

array('id'=>2,'name'=>'海淀','parent'=>7),

array('id'=>3,'name'=>'定州市','parent'=>5),

array('id'=>4,'name'=>'昌平','parent'=>7),

array('id'=>5,'name'=>'保定','parent'=>1),

array('id'=>6,'name'=>'朝阳','parent'=>7),

array('id'=>7,'name'=>'北京','parent'=>0),

array('id'=>8,'name'=>'上地','parent'=>2)

);

function subtree($arr,$id=0) {

   static $subs = array();

   foreach($arr as $k=>$v) {

      

      if($v['parent'] == $id) {

         $subs[] = $v;

         subtree($arr,$v['id']);

      }

   

   }

   return $subs;

}

print_r(subtree($area,0,1));

?>