JSON error in swift

Question

I am new to Swift and API programming and am running into the following error:

uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFNumber length]

This is the line that is causing this error:

print(json[“totalPostsByUser”])

For more context, this is a more complete code sample:

let jsonStr = NSString(data: request.HTTPBody!, encoding: NSUTF8StringEncoding)
let task = session.dataTaskWithRequest(request, completionHandler: { (data, response, error) -> Void in
   let httpResponse = response as? NSHTTPURLResponse
   var err: NSError?

   if httpResponse!.statusCode == 201 {
      if error == nil {
         let jsonStr = NSString(data: data!, encoding: NSUTF8StringEncoding)
         let jsonData: NSData = jsonStr!.dataUsingEncoding(NSUTF8StringEncoding)!
         do {
            if let json: AnyObject = try NSJSONSerialization.JSONObjectWithData(jsonData, options: NSJSONReadingOptions.AllowFragments) {
               let responseString = NSString(data: data!, encoding:  NSUTF8StringEncoding)
               print(responseString)
               print(json["totalPostsByUser"])
               totalPostsByUser = (json["totalPostsByUser"] as? Int)!
            }
         } catch let parseError {
         }
      }
   }
}

totalPostsByUser = (json["totalPostsByUser"] as? Int)! should either be totalPostsByUser = json["totalPostsByUser"] as! Int or totalPostsByUser = json["totalPostsByUser"] as? Int (hint, the second option is better) — Daniel Klöck
– Daniel Klöck, Commented May 25, 2016 at 8:10

Jigar Tarsariya · Accepted Answer · 2016-05-25 05:49:22Z

1

I think you need to replace some piece of code with below code,

if let json: NSMutableDictionary = try NSJSONSerialization.JSONObjectWithData(jsonData, options: NSJSONReadingOptions.AllowFragments) as? NSMutableDictionary
    {
               let responseString = NSString(data: data!, encoding:  NSUTF8StringEncoding)
               print(responseString)
               //print(json["totalPostsByUser"])
               print(json.valueForKey("totalPostsByUser"))
               //totalPostsByUser = (json["totalPostsByUser"] as? Int)!
    }

Convert anyObject to MutableDictionary which will be easy to extract value from key.

Hope this will help you.

answered May 25, 2016 at 5:49

Jigar Tarsariya

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1 Comment

Jigar Tarsariya Over a year ago

You are welcome :) and please accept this answer so it will be helpful to others also

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