三个一维数组 组装为一个二维数组

        foreach ($header as $index => $item) {
            $arr = [];
            $arr['title'] = $item;
            if (array_key_exists($index,$content)){
                $arr['new'] = $content[$index];
            }
            if (array_key_exists($index,$oldContent)){
                $arr['old'] = $oldContent[$index];
            }
            $message[] = $arr;
        }