【PHP】简单实现无限级分类

    /**
     * @Author: 小破孩嫩
     * @Email: 3584685883@qq.com
     * @Time: 2021/8/20 17:43
     * @param $arr
     * @return array
     * @Description：数据树，无限级分类
     */
    public function getTreeByDate($arr) {
        $items = [];
        foreach($arr as $v){
            $items[$v['id']] = $v;
        }
        $tree = [];
        foreach($items as $k => $item){
            if(isset($items[$item['pid']])){
                $items[$item['pid']]['child'][] = &$items[$k];
            }else{
                $tree[] = &$items[$k];
            }
        }
        return $tree;
    }