如何从swift3中的JSON字符串中分别获取键和值？

Posted 2023-03-05

【中文标题】如何从swift3中的JSON字符串中分别获取键和值？

【英文标题】：How to get the keys and values separately from the JSON string in swift3?

【发布时间】：2017-08-04 05:53:51

【问题描述】：

我有一个 JSON 字符串：

    "messages": null,
    "data": [
        
            "id": 27,
            "key": "ABC",
            "value": "5",
            "description": "Hi all"
        ,
        
            "id": 28,
            "key": "DEF",
            "value": "1",
            "description": "I am here"
        ]
 "status": 0

现在我需要获取键的值并使用核心数据中存在的值对其进行更新。 为此，我正在使用代码：

func updateAllRecords(responseArray: [ApplicationSettingsDataResponse]) 
    for settingsObject in responseArray 
    if #available(ios 10.0, *) 
      let request = NSFetchRequest<ApplicationSettings>(entityName: "ApplicationSettings")

      do 
        let context = persistentContainer.viewContext
        let searchResults = try context.fetch(request)

        for settingsKeys in searchResults 

        if  settingsKeys.key == settingsObject.key 
            settingsKeys.value = settingsObject.value
            try context.save()
          
        

       catch 
        print ("There was an error")
      

     else 

        
  
  

我这样做对吗？请查看此代码。

【问题讨论】：

您好，您的预期输出是什么

【参考方案1】：

首先将json响应转换为字典，您可以轻松获取键和值

let keys = jsonDict.flatMap  $0.0 

输出 [“状态”、“数据”、“消息”]

更多信息我创建了演示

import UIKit
func convertToDictionary(text: String) -> [String:Any]?

    if let data = text.data(using: .utf8)
    
        do 
            return try JSONSerialization.jsonObject(with: data, options: []) as? Dictionary
         catch 
            print(error.localizedDescription)
        
    
    return nil


let str = "\"messages\": 0,\"data\": [\"id\": 27,\"key\": \"ABC\",\"value\": \"5\",\"description\": \"Hi all\",\"id\": 28,\"key\": \"DEF\",\"value\": \"1\",\"description\": \"I am here\"],\"status\": 0"

let str2 = "\"messages\": 1,\"data\": [\"id\": 27,\"key\": \"ABC\",\"value\": \"5\",\"description\": \"Hi all\",\"id\": 28,\"key\": \"DEF\",\"value\": \"1\",\"description\": \"I am not here\"],\"status\": 1"


let replaceWithDict:[String:Any] = convertToDictionary(text: str) ?? ["test":"test"]
var resultDict:[String:Any] = convertToDictionary(text: str2) ?? ["test":"test"]
let keys = replaceWithDict.flatMap  $0.0
print(resultDict)
for key in keys
  resultDict.updateValue(replaceWithDict[key], forKey: key) 
print(resultDict)

输出

更新前

    ["status": 1, "data": <__NSArrayI 0x608000034900>(

    description = "Hi all";
    id = 27;
    key = ABC;
    value = 5;
,

    description = "I am not here";
    id = 28;
    key = DEF;
    value = 1;

)
, "messages": 1]

更新后

["status": Optional(0), "data": Optional(<__NSArrayI 0x600000033460>(

    description = "Hi all";
    id = 27;
    key = ABC;
    value = 5;
,

    description = "I am here";
    id = 28;
    key = DEF;
    value = 1;

)
), "messages": Optional(0)]