<?php//无限级分类$arr=array(array('id'=>1,'name'=>'HeNan','parent_id'=>0),array('id'=>2,'name'=>'nanyang','parent_id'=>1),array('id'=>3,'name'=>'tanghe','parent_id'=>2),array('id'=>4,'name'=>'HuBei','parent_id'=>0),array('id'=>5,'name'=>'wuhan','parent_id'=>4),array('id'=>6,'name'=>'FuJian','parent_id'=>0),array('id'=>7,'name'=>'xiamen','parent_id'=>6),array('id'=>8,'name'=>'huangshi','parent_id'=>5));//递归法找指定栏目的子孙树functionsubtree($data,$id=0,$lev=1){$arr=array();foreach($dataas$v){if($v['parent_id']==$id){$v['lev']=$lev;$arr[]=$v;$cid=$v['id'];$arr=array_merge($arr,subtree($data,$cid,$lev+1));}}return$arr;}//递归法找指定栏目的家谱树functionpartree($data,$id=0){$arr=array();foreach($dataas$v){if($v['id']==$id){$arr[]=$v;$cid=$v['parent_id'];$arr=array_merge(partree($data,$cid),$arr);}}return$arr;}//迭代法查找指定栏目的家谱树functionfpartree($data,$id=0){$arr=array();while($id!==0){foreach($dataas$v){if($v['id']==$id){$arr[]=$v;$id=$v['parent_id'];break;}}}returnarray_reverse($arr);}//排序输出$subtree=subtree($arr,0);foreach($subtreeas$v){echostr_repeat('&nbsp&nbsp',$v['lev']).$v['name'].'<br/>';}?>