如何訪問 NSDictionary 的索引，並將該鍵的值轉換為 Swift 中的 Int？

Question

我正在嘗試訪問 NSDictionary 的索引，並使用 Swift 將該鍵的值轉換為 Int。

我還使用 API 來獲取數據。 API 響應是我用來創建初始字典的內容，然后我根據 API 響應的“小時”部分創建字典。 我的代碼的 API 調用部分正在運行，因此我只包含與訪問 hoursDictionary 相關的代碼。

在網上查找此問題后，我嘗試使用 [[[String: Any]]] 而不是 [NSDictionary] for hoursDictionary，但這對我不起作用。

我不斷收到的錯誤是在 if 語句行：if Int(hoursDictionary[0][5][2]) > Integer for a certain time {, and the error text is: “Value of type 'Any?' 沒有下標”。 我知道這是因為我試圖訪問的 NSDictionary 的鍵值具有 Any 類型的值。

我認為錯誤出在這個 if 語句中的某個地方，並且與更改字典中我試圖訪問 Int 的那部分的數據類型有關。

我使用的 API 是 Yelp Fusion API，我使用的 API 搜索是“商家詳情”。 這是此文檔的鏈接： https://www.yelp.com/developers/documentation/v3/business 。

正在返回的 API 響應主體的示例以及我正在訪問的內容如下：

{
  "id": "WavvLdfdP6g8aZTtbBQHTw",
  "alias": "gary-danko-san-francisco",
  "name": "Gary Danko",
  "image_url": "https://s3-media2.fl.yelpcdn.com/bphoto/CPc91bGzKBe95aM5edjhhQ/o.jpg",
  "is_claimed": true,
  "is_closed": false,
  "url": "https://www.yelp.com/biz/gary-danko-san-francisco?adjust_creative=wpr6gw4FnptTrk1CeT8POg&utm_campaign=yelp_api_v3&utm_medium=api_v3_business_lookup&utm_source=wpr6gw4FnptTrk1CeT8POg",
  "phone": "+14157492060",
  "display_phone": "(415) 749-2060",
  "review_count": 5296,
  "categories": [
    {
      "alias": "newamerican",
      "title": "American (New)"
    },
    {
      "alias": "french",
      "title": "French"
    },
    {
      "alias": "wine_bars",
      "title": "Wine Bars"
    }
  ],
  "rating": 4.5,
  "location": {
    "address1": "800 N Point St",
    "address2": "",
    "address3": "",
    "city": "San Francisco",
    "zip_code": "94109",
    "country": "US",
    "state": "CA",
    "display_address": [
      "800 N Point St",
      "San Francisco, CA 94109"
    ],
    "cross_streets": ""
  },
  "coordinates": {
    "latitude": 37.80587,
    "longitude": -122.42058
  },
  "photos": [
    "https://s3-media2.fl.yelpcdn.com/bphoto/CPc91bGzKBe95aM5edjhhQ/o.jpg",
    "https://s3-media4.fl.yelpcdn.com/bphoto/FmXn6cYO1Mm03UNO5cbOqw/o.jpg",
    "https://s3-media4.fl.yelpcdn.com/bphoto/HZVDyYaghwPl2kVbvHuHjA/o.jpg"
  ],
  "price": "$$$$",
  "hours": [
    {
      "open": [
        {
          "is_overnight": false,
          "start": "1730",
          "end": "2200",
          "day": 0
        },
        {
          "is_overnight": false,
          "start": "1730",
          "end": "2200",
          "day": 1
        },
        {
          "is_overnight": false,
          "start": "1730",
          "end": "2200",
          "day": 2
        },
        {
          "is_overnight": false,
          "start": "1730",
          "end": "2200",
          "day": 3
        },
        {
          "is_overnight": false,
          "start": "1730",
          "end": "2200",
          "day": 4
        },
        {
          "is_overnight": false,
          "start": "1730",
          "end": "2200",
          "day": 5
        },
        {
          "is_overnight": false,
          "start": "1730",
          "end": "2200",
          "day": 6
        }
      ],
      "hours_type": "REGULAR",
      "is_open_now": false
    }
  ],
  "transactions": [],
  "special_hours": [
    {
      "date": "2019-02-07",
      "is_closed": null,
      "start": "1600",
      "end": "2000",
      "is_overnight": false
    }
  ]
}

我的代碼片段：

FetchData.swift

                        /// Read data as JSON
                        let json = try JSONSerialization.jsonObject(with: data!, options: [])
                        
                        /// Main dictionary
                        guard let responseDictionary = json as? NSDictionary else {return}
                        
                        /// Creating hours dictionary,
                        guard let hoursDictionary = responseDictionary.value(forKey: "hours") as? [NSDictionary] else {return}
                        
                        if let endTimeAsString = hoursDictionary["open"][5]["end"] as? String,
                        let endTimeAsInt = Int(endTimeAsString),
                        endTimeAsInt > An integer representing a certain time {

                          // Do something
                            
}                   

Answer 1

您不能像訪問數組那樣訪問字典的 [nth] 索引，因為字典是無序集合。 相反，你必須做這樣的事情[CORRECTED] hoursDictionary[0]["open"][5]["end"] ，或者任何順序來獲得你需要的值。

或者，我傾向於將其拆分，以便確保我正確地處理每個步驟，如下所示：

guard let hoursDictionaries = responseDictionary.value(forKey: "hours") as? [NSDictionary] else {return}
                        
if let firstHoursDictionary = hoursDictionaries[0] as? NSDictionary,
   let openDictionarys = firstHoursDictionary["open"] as? [NSDictionary],
   let firstOpenDictionary = openDictionarys[5] as? NSDictionary,
   let endTimeAsString = firstOpenDictionary["end"] as? String,
   let endTimeAsInt = Int(endTimeAsString),
   endTimeAsInt > someInt {

    // Do something
}

// Remember, you can always check what type the compiler is inferring something 
// to be by right-clicking on the variable name and clicking `Show Quick Help`.