Swift 3：从返回nil访问嵌套字典吗？

Question

我在尝试访问嵌套的Dictionary遇到问题，该Dictionary似乎返回nil 。

这是我的info输出的类型Dictionary<String, Any> ：

info = ["list_order": 1, "name": Some Text, "id": 1, "menu_items": {
    1 =     {
        "food_name" = "String";
        "food_picture" = "link";
        "food_price" = "2.00";
    };
    2 =     {
        "food_name" = "String";
        "food_picture" = "link";
        "food_price" = "5.00";
        id = 2;
    };
}]

info["menu_items"]的输出：

info["menu_items"] = {
    1 =     {
        "food_name" = "String";
        "food_picture" = "link";
        "food_price" = "2.00";
        id = 1;
    };
    2 =     {
        "food_name" = "String";
        "food_picture" = "link";
        "food_price" = "5.00";
        id = 2;
    };
}

但是，以下分配在test产生nil ：

let test = info["menu_items"] as? Dictionary<Int, Any>

有什么不明显的东西还是我不了解基本原理？

Answer 1

如果您的键不是Int类型，则很可能是String类型，请使用[String: Any]尝试一次。

if let menuItems = info["menu_items"] as? [String: Any] {
     print(menuItems)
}