快速删除json响应中的空值

Posted 2023-03-15

【中文标题】快速删除json响应中的空值

【英文标题】：remove null values in json response swift

【发布时间】：2018-07-17 05:15:32

【问题描述】：

我收到了这个错误：

Could not cast value of type 'NSNull' (0x1114e4850) to 'NSString' (0x11065d2a8).

//These are my arrays
var snoArray:[Int] = []
var quote_idArray:[String] = []
var quote_amountArray:[String] = []
var dateArray:[String] = []
var timeArray:[String] = []
var perkilometerArray:[String] = []
var pertonArray:[String] = []

//My JSON response is like this.
["Response": 
Array =     (
            
        date = "25-05-2018";
        perkilometer = 2;
        perton = "<null>";
        "quote_amount" = 1234;
        "quote_id" = 5b080f8aa082c;
        sno = 1;
        time = "18:58";
    ,
            
        date = "25-05-2018";
        perkilometer = 346;
        perton = "<null>";
        "quote_amount" = 230000;
        "quote_id" = 5b080ed57aa34;
        sno = 2;
        time = "18:55";
    
);
"error_code" = 0;
message = SUCCESS;
status = SUCCESS;
, "count": 2]

//I'm catching response like this...
if status == "SUCCESS" 
   if let array = res!["Array"] as? Array<Dictionary<String, Any>> 
      //    print(array.count)
      self.snoArray = array.map  $0["sno"]!  as! [Int]
      self.quote_idArray = array.map  $0["quote_id"]!  as! [String]
      self.quote_amountArray = array.map  $0["quote_amount"]!  as! [String]
      self.dateArray = array.map  $0["date"]!  as! [String]
      self.timeArray = array.map  $0["time"]!  as! [String]
      self.perkilometerArray = array.map  $0["perkilometer"]!  as! [String]
      //But here I'm getting null values and app crashed
      self.pertonArray = array.map  $0["perton"]!  as! [String]
   
 

//When I write like this, it's printing : [<null>, <null>]
let perTon = array.compactMap( $0 ["perton"])
 print(perTon) // Output: [<null>, <null>]

我参考了这个链接：https://useyourloaf.com/blog/swift-non-nil-values-in-an-array-of-optionals/

这里我想从 self.pertonArray 中删除空值并想打印空 self.pertonArray([ , ])。

如果假设我得到这样的响应如何解决这个问题。

["Response": 
Array =     (
            
        date = "25-05-2018";
        perkilometer = 2;
        perton = "something";
        "quote_amount" = 1234;
        "quote_id" = 5b080f8aa082c;
        sno = 1;
        time = "18:58";
    ,
            
        date = "25-05-2018";
        perkilometer = 346;
        perton = "<null>";
        "quote_amount" = 230000;
        "quote_id" = 5b080ed57aa34;
        sno = 2;
        time = "18:55";
    
);
"error_code" = 0;
message = SUCCESS;
status = SUCCESS;
, "count": 2] 

如何解决这个问题....

【问题讨论】：

不要将其转换为字符串使用像"\(yourVariable)"这样的字符串插值不会导致崩溃

@Devil Decoder 可以发一下答案吗，我接受...

不要强行解包，这样可以避免更多崩溃。使用保护让/如果让。

@Sharad Chauhan 你能为我发布最佳解决方案吗？

Swift: How to remove a null value from Dictionary?的可能重复

【参考方案1】：

绑定时有很多方法可以从 JSON 中删除 nil。 但是根据您的代码，这是一个。

if status == "SUCCESS" 
   if let array = res!["Array"] as? Array<Dictionary<String, Any>> 
      //    print(array.count)
      self.snoArray = array.map  ($0["sno"] as? Int) ?? 0 
      self.quote_idArray = array.map  ($0["quote_id"] as? String) ?? "" 
      self.quote_amountArray = array.map  ($0["quote_amount"] as? String) ?? "" 
      self.dateArray = array.map  ($0["date"] as? String) ?? "" 
      self.timeArray = array.map  ($0["time"] as? String) ?? "" 
      self.perkilometerArray = array.map  ($0["perkilometer"] as? String) ?? "" 

      // You get error here with null values
      // here is how it's fixed
      self.pertonArray = array.map  ($0["perton"] as? String) ?? "" 
   
 

在绑定 json 时最好不要使用Force Unwrapping，因为您永远无法确定不会有空或不正确的数据（您期望 Int 但值是从服务器发送的字符串）。

【讨论】：

我在等你的答复。请回复我。

【参考方案2】：

使用字符串插值解析值

喜欢你的回复

你想得到perton

let value = ((responce as! Array)[indexofarray] as! Dictionary<string,any>)["perton"]
let perton = "\(value ?? "")"

这将为第一个索引返回something，对于第二个索引，它将返回字符串中的<null>