子菜单数组方式

public function index(){    $class_list = Category::orderBy('category_parent_id', 'asc')->orderBy('category_sort', 'asc')->orderBy('category_id', 'asc')->get()->toArray();    $gc_list = array();    foreach ($class_list as $key => $value) {        $p_id = $value['category_parent_id'];//父级ID        $cate_id = $value['category_id'];        if ($p_id == 0) {//第1级分类            $gc_list[$cate_id] = $value;        } elseif (array_key_exists($p_id, $gc_list)) {//第2级            $class2_ids[$cate_id] = $p_id;            $gc_list[$p_id]['class2'][$cate_id] = $value;        }    }         dd($gc_list);    return view('category.index', ['list' => $gc_list]);}