casting - 如何将 Array 转换为空数组变量？

Question

问题:我无法将字符串数组(类型为“AnyObject”)分配给空数组。

步骤:
1. 获取包含字符串和数组的字典。
2. 通过键“photos”从该字典中获取一个数组。
注意:Xcode 的警告建议我给出显式类型“AnyObject”。
3. 创建一个空数组。
4.尝试分配(失败)。

let responseDictionary = responseDict as [String : AnyObject]
let ricPhotos:AnyObject = responseDictionary["photos"]!              
var thePhotos:Array<AnyObject>?              
thePhotos = ricPhotos  <--- fails

编译器错误:

...'AnyObject' is not convertible to 'Array<AnyObject>'

问题:如何将“ricPhotos”分配给空数组“thePhotos”，并最好将“AnyObject”转换为“String”？

<小时/> 修订

let responseDictionary = responseDict as [String : AnyObject]
var anyObject: AnyObject? = responseDictionary["photos"]

好吧，‘anyObject’看起来是一个字典，里面是‘photo’，它是一个数组；如数据所示。以下是一些数据(anyObject):

{
    page = 1;
    pages = 1334;
    perpage = 100;
    photo =     (
                {
            farm = 3;
            "height_m" = 336;
            "height_s" = 161;
            "height_sq" = 75;
            "height_t" = 67;
            id = 15166756998;
            isfamily = 0;
            isfriend = 0;
            ispublic = 1;
            owner = "127012961@N08";
            secret = 053032f300;
            server = 2941;
            title = "You @NYPL";
            "url_m" = "https://farm3.staticflickr.com/2941/15166756998_053032f300.jpg";
            "url_s" = "https://farm3.staticflickr.com/2941/15166756998_053032f300_m.jpg";
            "url_sq" = "https://farm3.staticflickr.com/2941/15166756998_053032f300_s.jpg";
            "url_t" = "https://farm3.staticflickr.com/2941/15166756998_053032f300_t.jpg";
            "width_m" = 500;
            "width_s" = 240;
            "width_sq" = 75;
            "width_t" = 100;
        },
        ...etc.

我想获取“照片”数组。但我无法将“anyObject”向下转换为“Dictionary”，以便我可以为其添加下标。我尝试过:

var anyObject:Dictionary = responseDictionary["photos"]

但是我得到了:

'(String, AnyObject)' is not convertible to '[String : AnyObject]'

所以我坚持:

var anyObject: AnyObject? = responseDictionary["photos"]

因此，使用anyObject，我尝试访问“照片”:

let RicPhotos = anyObject["Photo"] as [String : AnyObject]

...我也尝试过:

let RicPhotos = anyObject["Photo"] as Array<Dictionary<String,String>>

但是我得到了:

'AnyObject?' does not have a member named 'subscript'

我可以看到数据，但无法提取到空变量中。
我尝试向下转换为特定类型(字典)，但编译器拒绝。

必须有一种直接的方法可以从字典中获取嵌入数组，同时转换为相应的转换(没有“anyObject”)。

有什么想法吗？

Answer 1

编辑了我的答案以适应您的编辑...

let responseDictionary = [:] as [String : AnyObject]
var photosDic: AnyObject? = responseDictionary["photos"]
if let photosDic = photosDic as? Dictionary<String, AnyObject> {
    var photosArray: AnyObject? = photosDic["photo"]
    if let photosArray = photosArray as? Array<Dictionary<String, AnyObject>> {
        //There you go
    }
}