如何为动态键、json解析、swift5创建模型
如何为动态键、json解析、swift5创建模型
提问于 2020-11-04 10:47:04
我正在解析json数据，并试图创建一个模型，但无法找到如何实现标题并从json数据(我提供的)中提取属性，因为pageids属性是动态的。请告诉我如何创建模型，使用id (存储在title属性中)从页面中提取pageids属性。
我试了一下，下面是我的代码，但我不认为这是正确的
var ID = ""
struct Document:Codable {
let batchcomplete:String
let query:Query
}
struct Query:Codable {
let normalized:[Normalized]
let pages:Pages
var pageids:[String]{
didSet{
ID = oldValue[0]
}
}
}
struct Normalized:Codable {
let from:String
let to:String // it is a name of an flower
}
struct Pages:Codable {
let id:[Pages2]
enum CodingKeys:CodingKey {
case id = "\(ID)"
}
}
struct Pages2:Codable {
let title:String // this is an official name of flower
let extract:String // this is a body
let thumbnail:Thumbnail
}
struct Thumbnail:Codable {
let source:String //this is an url for photo
}Stack Overflow用户
回答已采纳
发布于 2020-11-06 11:34:28
映射您的JSON的模型如下所示：
struct Document: Codable {
let batchcomplete: String
let query: Query
}
struct Query: Codable {
let normalized: [Normalized]
var pageids: [String]
let pages: [String: Page]
}
struct Normalized: Codable {
let from: String
let to: String
}
struct Page: Codable {
let title: String
let extract: String
let thumbnail: Thumbnail
}
struct Thumbnail: Codable {
let source: String
}您可以使用pageids数组和pages字典访问每个页面：
let decoder = JSONDecoder()
do {
let decoded = try decoder.decode(Document.self, from: Data(jsonString.utf8))
decoded.query.pageids.forEach { id in
guard let page = decoded.query.pages[id] else { return }
print(page.title)
}
} catch {
print(error)
}然而，我更愿意对模型做一个小的修改，以便更容易地访问页面。这将需要定制地实现Query结构的解码：
struct Query: Decodable {
let normalized: [Normalized]
let pages: [Page]
enum CodingKeys: String, CodingKey {
case normalized
case pageids
case pages
}
init(from decoder: Decoder) throws {
let container = try decoder.container(keyedBy: CodingKeys.self)
normalized = try container.decode([Normalized].self, forKey: .normalized)
let pageids = try container.decode([String].self, forKey: .pageids)
let pagesDict = try container.decode([String: Page].self, forKey: .pages)
pages = pageids.compactMap { pagesDict[$0] }
}
}那么，访问每个页面就像一个循环一样简单：
let decoder = JSONDecoder()
do {
let decoded = try decoder.decode(Document.self, from: Data(jsonString.utf8))
decoded.query.pages.forEach { page in
print(page.title)
}
} catch {
print(error)
}页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/64678573
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