如何在没有密钥的情况下解析 JSON 文件？

Posted 2023-02-24

【中文标题】如何在没有密钥的情况下解析 JSON 文件？

【英文标题】：How I can parse JSON file without keys?

【发布时间】：2017-04-21 14:23:24

【问题描述】：

我已经从这个网址下载了 JSON 文件：https://raw.githubusercontent.com/David-Haim/CountriesToCitiesJSON/master/countriesToCities.json

我将所有 JSON 文件解析为 let json 后卡住了

 let requestURL: NSURL = NSURL(string: "https://raw.githubusercontent.com/David-Haim/CountriesToCitiesJSON/master/countriesToCities.json")!
    let urlRequest: NSMutableURLRequest = NSMutableURLRequest(URL: requestURL)
    let session = NSURLSession.sharedSession()
    let task = session.dataTaskWithRequest(urlRequest) 
        (data, response, error) -> Void in

        let httpResponse = response as! NSHTTPURLResponse
        let statusCode = httpResponse.statusCode

        if (statusCode == 200) 

            do

                let json = try NSJSONSerialization.JSONObjectWithData(data!, options:.AllowFragments)

                print (json)
            catch 
                print("Error with Json: \(error)")
            

        
    

    task.resume()

问题是我不能转向每个国家和每个城市，因为我不知道 key->value。我怎样才能转向每个国家和城市？

【问题讨论】：

Iterating Through a Dictionary in Swift的可能重复

查看 Swift 文档 developer.apple.com/library/content/documentation/Swift/… 遍历字典

【参考方案1】：

这里有一些 Swift Playground 代码可以完全满足您的需求：

//: Playground - noun: a place where people can play
import UIKit
import PlaygroundSupport

PlaygroundPage.current.needsIndefiniteExecution = true

let urlStr = "https://raw.githubusercontent.com/David-Haim/CountriesToCitiesJSON/master/countriesToCities.json"

let requestURL: URL = URL(string: urlStr)!
let urlRequest: URLRequest = URLRequest(url: requestURL)
let session = URLSession.shared
let task = session.dataTask(with: urlRequest) 
    (data, response, error) -> Void in

    let httpResponse = response as! HTTPURLResponse
    let statusCode = httpResponse.statusCode

    if (statusCode == 200) 
        do
            let json:[String:[String]] = try! JSONSerialization.jsonObject(with: data!, options:.allowFragments) as! Dictionary
            for (country, cities) in json 
                print(country)
                for city in cities 
                    print("City in \(country): \(city)")
                
            


        catch 
            print("Error with Json: \(error)")
        

     else 
        print("Other status: \(statusCode)")
    


task.resume()

他们的关键是知道数据的格式，在本例中是包含 String 键和 String 值数组的字典。当你声明你的 json 变量时，将它转换为它的实际值：

let json:[String:[String]] = try! JSONSerialization.jsonObject(with: data!, options:.allowFragments) as! Dictionary

【讨论】：

它的作品。非常感谢你。现在对我来说很清楚

【参考方案2】：

在此回复中，您可以找到有关国家和城市的所有数据。

您的响应是字典 [String:[String]] 类型。

例子：

部分回复：

let json = ["Eritrea":["Asmara",""],"Cuba":["Havana","Habana","La Habana","Matanzas","Villa","Bayamo","Cienfuegos","Santiago de Cuba","Holguín","Ciego de Ãvila","Pinar del Río","Sancti Spíritus","Camagüey","Las Tunas","Guantánamo","Varadero"],"Saint Helena":["Tristan Da Cunha","Jamestown"],"Christmas Island":["Flying Fish Cove"],"Ethiopia":["Addis Ababa","Awasa","Jijiga"],"British Indian Ocean Territory":[""]]

因此，如果您想获取所有国家/地区名称，只需这样做：

let keys = Array(json.keys)

如果您想获取例如 厄立特里亚 的城市，请执行以下操作：

let cityes = json["Eritrea"]