Swift JSON 解析访问数组

Posted 2023-03-15

【中文标题】Swift JSON 解析访问数组

【英文标题】：Swift JSON Parsing Access Array

【发布时间】：2018-07-01 13:33:10

【问题描述】：

我正在从Open - Elevation 中提取一个 JSON 文件，但是我无法从我提取的数据中访问数组的各个部分。我当前的视图控制器中有 JSON 解析代码，它还允许我读取它自己的整个数组。

struct ElevationArray: Decodable 
    let results: [results]


struct results: Decodable 
    let latitude: Double
    let longitude: Double
    let elevation: Double

    init(json: [String: Any])
      latitude = json["latitude"] as? Double ?? 0.0
      longitude = json["longitude"] as? Double ?? 0.0
      elevation = json["elevation"] as? Double ?? 0.0

    


class FlightInfo: UITableViewController 


    @IBOutlet weak var Lat: UILabel!
    @IBOutlet weak var Long: UILabel!
    @IBOutlet weak var Elevation_label: UILabel!

    var elevationmain: Double?

    override func viewDidLoad() 
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        Lat.text = "\(publocation.latitude)"
        Long.text = "\(publocation.longitude)"

        ElevationJSON()


    


    override func didReceiveMemoryWarning() 
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    

    func ElevationJSON()

        let jsonURLString = "https://api.open-elevation.com/api/v1/lookup?locations=41.161758,-8.583933"
        guard let url = URL(string: jsonURLString) else return

        URLSession.shared.dataTask(with: url)  (data, response, err) in
            //perhaps check err
            //also perhaps check response status 200 OK

            guard let data = data else  return 


            do 
                //let websiteDescription = try JSONDecoder().decode(WebsiteDescription.self, from: data)
               // print(websiteDescription.name, websiteDescription.description)

               let eleresults = try JSONDecoder().decode(ElevationArray.self, from: data)
               print(eleresults.results)

                let eletest = eleresults.results

                print(eletest)

                //self.elevationmain = Double(eleresults.results)
             catch let jsonErr 
                print("Error serializing json:", jsonErr)
            



            .resume()
    

这是我在运行应用程序并打印出数组时得到的控制台输出。 enter image description here

【参考方案1】：

eleresults.results（或eletest）是results的数组。

要访问所有数据，请使用循环：

for result in eletest 
    print(result.elevation)

如果你只想要第一个结果：

if let result = eletest.first 
    print(result.elevation)

顺便说一句 - 你的 results 结构应该重命名为有用的东西，例如 Elevation 或比 results 更多的描述（注意它应该以大写字母开头。