解码错误-预期对Dictionary< String，Any>进行解码但是找到了一个数组 [英] Decoding Error -- Expected to decode Dictionary<String, Any> but found an array instead

问题描述

我是快速编程和Xcode的新手，我尝试使用Json编码将mysql数据从数据库调用到Xcode.我能够成功地调用所有数据(数组)，但是当我决定仅调用一个值(列)时，说Courses.name，我得到解码错误-期望对Dictionary进行解码，但是找到了一个数组".我该如何解决这个问题?我的目标是仅打印course.name

I am new to swift programming and Xcode and am try to call mysql data from the database to Xcode using Json encoding. I was able to successfully call all the data (array) but when I decide to call only one value(column) say Courses.name I get the "Decoding Error -- Expected to decode Dictionary but found an array instead." How do I work my way around this problem? My goal is to print only courses.name

import UIKit

struct Course: Decodable {
let id: String
let name: String
let member:  String

 }

class ViewController: UIViewController {

override func viewDidLoad() {
    super.viewDidLoad()

    let jsonUrlString = "http://oriri.ng/aapl/service.php"
    guard let url = URL(string: jsonUrlString) else
    { return }

    URLSession.shared.dataTask(with: url) { (data, response, err) in

        guard let data =  data else{ return }

        do {

            let courses = try JSONDecoder().decode(Course.self, from: data)
            print(courses.name)


        } catch let jsonErr {
            print("Error serializing json:", jsonErr)
        }

    }.resume()

   }
}

推荐答案

[{"id":"1"，"name":"sobande_ibukun"，"member":"blue"}]

[{"id":"1","name":"sobande_ibukun","member":"blue"}]

周围的[]表示它是一个数组.用以下代码解码，它应该可以工作:

The [] around denotes that it is an array. Decode with the following and it should work:

let courses = try JSONDecoder().decode([Course].self, from: data)

如果您确定它始终是一门课程，则可以执行以下操作:

If you are sure that it will always be one course you can do:

print(courses.first!.name)

如果可能有很多课程，您可以打印每个名称:

If there may be many courses you can print every name:

courses.forEach { course in print(course.name) }

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