php无限极数组分类

 /**
     * 无限极分类
     * @param array $data         分类数据
     * @param int $pid            父ID
     * @param int $level          层级数
     * @return array              分类数组
     */
    public function getTree($data, $pid = 0, $level = 0) {
        $tree = [];
        foreach ($data as $val) {
            if ($val['pid'] == $pid) {
                $val['level'] = $level;
                $val['children'] = $this->getTree($data, $val['id'], $level + 1);
                $tree[] = $val;
            }
        }
        return $tree;
    }