Swift Codable 词典

Question

我在进行可编码时遇到了问题。任何帮助将不胜感激。我的操场上有以下东西

我的 JSON 文件中的示例。它有更多的元素，减少了它一个更小的子集。

{
  "metadata" : {
    "generated" : {
      "timestamp" : 1549331723,
      "date" : "2019-02-04 20:55:23"
    }
  },
  "data" : {
    "CA" : {
      "country-id" : 25000,
      "country-iso" : "CA",
      "country-eng" : "Canada",
      "country-fra" : "Canada",
      "date-published" : {
        "timestamp" : 1544561785,
        "date" : "2018-12-11 15:56:25",
        "asp" : "2018-12-11T15:56:25.4141468-05:00"
      }
    },
    "BM" : {
      "country-id" : 31000,
      "country-iso" : "BM",
      "country-eng" : "Bermuda",
      "country-fra" : "Bermudes",
      "date-published" : {
        "timestamp" : 1547226095,
        "date" : "2019-01-11 12:01:35",
        "asp" : "2019-01-11T12:01:35.4748399-05:00"
      }
    }
  }
}

来自快速输入应用程序。它为 Datum 生成了一个字典。 json 的结构方式，国家/地区缩写没有标签。

import Foundation

// MARK: - Welcome
struct Welcome: Codable {
    let metadata: Metadata?
    let data: [String: Datum]?
}

// MARK: - Datum
struct Datum: Codable {
    let countryID: Int?
    let countryISO, countryEng, countryFra: String?
    let datePublished: DatePublished?

    enum CodingKeys: String, CodingKey {
        case countryID = "country-id"
        case countryISO = "country-iso"
        case countryEng = "country-eng"
        case countryFra = "country-fra"
        case datePublished = "date-published"
    }
}

// MARK: - DatePublished
struct DatePublished: Codable {
    var timestamp: Int
    var date, asp: String
}

// MARK: - Metadata
struct Metadata: Codable {
    var generated: Generated
}

// MARK: - Generated
struct Generated: Codable {
    var timestamp: Int
    var date: String
}

// MARK: - Encode/decode helpers

class JSONNull: Codable, Hashable {

    public static func == (lhs: JSONNull, rhs: JSONNull) -> Bool {
        return true
    }

    public var hashValue: Int {
        return 0
    }

    public func hash(into hasher: inout Hasher) {
        // No-op
    }

    public init() {}

    public required init(from decoder: Decoder) throws {
        let container = try decoder.singleValueContainer()
        if !container.decodeNil() {
            throw DecodingError.typeMismatch(JSONNull.self, DecodingError.Context(codingPath: decoder.codingPath, debugDescription: "Wrong type for JSONNull"))
        }
    }

    public func encode(to encoder: Encoder) throws {
        var container = encoder.singleValueContainer()
        try container.encodeNil()
    }
}

从我的代码中，我可以加载 json 文件，我不确定如何使用字典处理此处的数据，并且国家/地区没有国家/地区缩写名称。

 guard let url = Bundle.main.url(forResource: "data", withExtension: "json") else { return 0 }

        let jsonData = try Data(contentsOf: url)

注意：这是对我之前的问题的跟进：Swift Codable Parsing keyNotFound

Answer 1

您的数据模型已正确定义（但是，我建议更改一些名称并从属性中删除 mutability/optionality）。

一旦解析了 JSON，就没有必要保留 Dictionary，因为键实际上是 country-iso 键下值的一部分。

因此，一旦您解码了 Root 对象，我建议您只保留 root.data.values，这样您就可以轻松处理 Array<CountryData>。

struct Root: Codable {
    let data: [String: CountryData]
}

struct CountryData: Codable {
    let countryID: Int
    let countryISO, countryEng, countryFra: String
    let datePublished: DatePublished

    enum CodingKeys: String, CodingKey {
        case countryID = "country-id"
        case countryISO = "country-iso"
        case countryEng = "country-eng"
        case countryFra = "country-fra"
        case datePublished = "date-published"
    }
}

// MARK: - DatePublished
struct DatePublished: Codable {
    let timestamp: Int
    let date, asp: String
}

do {
    let root = try JSONDecoder().decode(Root.self, from: countryJson.data(using: .utf8)!)
    let countries = root.data.values
    print(countries)
} catch {
    error
}

Swift Codable 词典

Swift Codable Dictionary

json

swift

codable