Predicate on optional value in swift not working

Question

I am try to predicate on the optional value and it always crash the application with following error.

* Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[ valueForUndefinedKey:]: this class is not key value coding-compliant for the key q_id.' * First throw call stack:

Although there is variable define in the model but it is define like this

var q_id : Int!

If i convert this variable in unwrap it workings fine

var q_id = Int()

So is there any other way for predicate on optional value?

let Qid = dictData.objectForKey("q_id") as? String
let fQuesID : Int  = Int(Qid!)!;

let predicate = NSPredicate(format: "SELF.q_id  ==  %i",fQuesID)
let arrObj : NSArray =  arrData.filteredArrayUsingPredicate(predicate) ;
            //arrData.filter { predicate.evaluateWithObject($0) }
if(arrObj.count > 0)
{
   let objPostModel : ViewPostModel = arrObj.firstObject as! ViewPostModel;
   objPostModel.isPollExpired = 1;  // 1 Means Poll Expired!
   self.tblViewPost?.reloadData();
}

It is only happened in primitive optional types variable (int,float,etc ... )

Update: If you make primitive type unoptional then it is working fine

_So is there any other way for predicate on optional value?_ depends on what you really want to do. Can you show me a pseudo code describing what you want to do if `q_id` is accessible? — OOPer, Jul 15 '16 at 10:05
I using this for updating the question with it's respective answer... — Chirag Shah, Jul 15 '16 at 12:37

score 3 · Accepted Answer · answered Jul 15 '16 at 14:01

I assume dictData is an NSDictionary containing String value for key "q_id", arrData is an NSArray which contains only ViewPostModel. And in the class ViewPostModel, q_id is a property of type Int?.

With all those given, you can write your code in some more Swifty way:

    if let
        qId = dictData["q_id"] as? String,
        fQuesID = Int(qId)
    {
        let arrObj = (arrData as! [ViewPostModel]).filter{$0.q_id == fQuesID}
        if let objPostModel = arrObj.first {
            objPostModel.isPollExpired = 1  // 1 Means Poll Expired!
            self.tblViewPost?.reloadData()
        }
    } else {
        print("invalid q_id in dictData")
    }

(With declaring your arrData as [ViewPostModel], you will have no need to use dangerous as! operator. You can make some other parts more Swifty.)

Generally, if you are using NSPredicate only to filter an array, better use Swift filter method and closure.

thanks for your quick reply.. Let me check this logic – Chirag Shah Jul 16 '16 at 05:26 — Chirag Shah, Jul 16 '16 at 05:26

Predicate on optional value in swift not working

1 Answers1