CODEWITHSUNDEEP
iosarraysswiftintxcode6
Leighton
Leighton

Reputation: 6679

Cannot invoke 'init' with argument of type 'NSNumber' (Swift)

I am trying to use 'weights' array to fill a graph with the below fetch request. But I am getting the error "Cannot invoke 'init' with argument of type 'NSNumber' and I have no idea why. 'weights' array should be an array of UInt16.

var weights : [Int16] = []


func weightFetchRequest() -> NSFetchRequest {
            let appDelegate = UIApplication.sharedApplication().delegate as AppDelegate
            let managedContext = appDelegate.managedObjectContext!
            let fetchRequest = NSFetchRequest(entityName: "Assessment")
            fetchRequest.sortDescriptors = [NSSortDescriptor(key: "nsDateOfAssessment", ascending: true)]
            var error: NSError?

            let fetchedResults = managedContext.executeFetchRequest(fetchRequest, error: &error) as [Assessment]?

            if let assessments = fetchedResults {
                let weightss = assessments.map { assessment in assessment.weight }

                weights = weightss

                println(weights)
                println(weightss)
            }
            return fetchRequest
        }

func lineChartView(lineChartView: JBLineChartView!, verticalValueForHorizontalIndex horizontalIndex: UInt, atLineIndex lineIndex: UInt) -> CGFloat {
        if (lineIndex == 0) {
            return CGFloat(weights[Int16(horizontalIndex)] as NSNumber) //Error here
        }
        return 0
    }

Upvotes: 1

Views: 2477

Answers (1)

Martin R
Martin R

Reputation: 539845

There are two problems in the line

return CGFloat(weights[Int16(horizontalIndex)] as NSNumber)
  • weights[Int16(horizontalIndex)] does not compile because an Int16 cannot be an array subscript. It should be weights[Int(horizontalIndex)].
  • weights[...] as NSNumber does not compile because there is no automatic bridging between the fixed-size integer types and NSNumber, it should be NSNumber(short: weights[...]).

So this would compile and work:

return CGFloat(NSNumber(short: weights[Int(horizontalIndex)]))

However, there is no need to use NSNumber in between, it can be simplified to

return CGFloat(weights[Int(horizontalIndex)])

Upvotes: 1

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