无限极分类，子集跟着父集排列，用于后台显示菜单页

<?php 
namespace Home\Clas;
class Cate{
    static public function unlimitedForLevel($data,$html=‘|__‘,$pid=0,$level=0){
        $arr=array();
        foreach ($data as $v) {
            if ($v[‘pid‘]==$pid) {
                $v[‘level‘]=$level+1;
                $v[‘html‘]=str_repeat($html, $level);
                $arr[]=$v;
                $arr=array_merge($arr,self::unlimitedForLevel($data,$html,$v[‘id‘],$level+1));
            }
        }
        return $arr;
    }
}

 ?>

<?php
namespace Home\Controller;
use Think\Controller;
use Home\Clas\Cate;
class IndexController extends Controller {
    public function index(){
        $data=array(
                ‘0‘=>array(
                        ‘id‘=>1,
                        ‘pid‘=>0
                    ),
                ‘1‘=>array(
                        ‘id‘=>2,
                        ‘pid‘=>0
                    ),
                ‘2‘=>array(
                        ‘id‘=>3,
                        ‘pid‘=>1
                    ),
                ‘3‘=>array(
                        ‘id‘=>4,
                        ‘pid‘=>3
                    )
            );
        $data=Cate::unlimitedForLevel($data);
        dump($data);die;
        $this->display();
            }
}