如何访问 NSDictionary 的索引，并将该键的值转换为 Swift 中的 Int？

Question

我正在尝试访问 NSDictionary 的索引，并使用 Swift 将该键的值转换为 Int。

我还使用 API 来获取数据。我使用 API 响应来创建初始字典，然后根据 API 响应的“小时”部分创建字典。我的代码的 API 调用部分正在运行，因此我只包含与访问 hoursDictionary 相关的代码。

在网上查找这个问题后，我尝试使用 [[[String: Any]]] 而不是 [NSDictionary] 来处理hoursDictionary，但这对我不起作用。

我不断收到的错误位于 if 语句行： if Int(hoursDictionary[0][5][2]) >某个时间的整数 { ，错误文本为：“Value of type 'Any?'没有下标”。我知道这是因为我尝试访问的 NSDictionary 的键值具有 Any 类型的值。

我认为错误出现在这个 if 语句中的某个地方，并且与更改我试图访问 Int 的字典中该部分的数据类型有关。

我使用的 API 是 Yelp Fusion API，我使用的 API 搜索是“商家详细信息”。以下是此文档的链接：https://www.yelp.com/developers/documentation /v3/business 。

返回的 API 响应正文和我正在访问的内容的示例如下：

{
  "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
    }
  ]
}

我的代码片段：

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

您无法像访问数组一样访问字典的 [nth] 索引，因为字典是一个无序集合。相反，您必须执行类似 [CORRECTED] hoursDictionary[0]["open"][5]["end"] 的操作，或任何序列来获取您需要的价值。

或者，我倾向于将其分开，这样我就可以确保我正确地处理每个步骤，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`.