递归的实例

刚出来混的时候，对递归不是特别懂，后来多研究了会儿，这时候把之前的东西补上，汇成文档的形式记录下来。

 //递归无限极分类
    private function makeTree($list,$pk = 'id', $pid='pid',$name='child',$root=0)
    {
        $tree = array();
        foreach ($list as $key=>$val){
            if ($val[$pid] == $root){
                unset($list[$key]);
                if (!empty($list)){
                    $tmpChild = self::makeTree($list,$pk,$pid,$name,$val[$pk]);
                    if (!empty($tmpChild)){
                        $val[$name] = $tmpChild;
                    }
                }
                $tree[] = $val;
            }
        }
        return $tree;
    }

如果调用的话，可以像下面的

 $province = DB::select("select 0 as pid,Code as id,Name from fl_province order by code");
        $city = DB::table('fl_city')
            ->select('ProAdCode as pid','CityAdCode as id','Name')
            ->get()->toArray();
        $county = DB::table('fl_county')
            ->select('AdminCode as id','CityAdCode as pid','Name')
            ->get()->toArray();
        $data = array_merge($province,$city,$county);
        foreach ($data as $v)
        {
            $list[] = [
                'value' => $v->id,
                'pid' => $v->pid,
                'label' => $v->Name,
            ];
        }

        $list = $this->makeTree($list,'value','pid','children',0);
        return $list;

这个是用的省市县三级来测试的，在有些菜单想要是下面图片的树结构的时候，就可以使用此方法来做。