Is there a better way to get numbers from dictionary (JSON data)? - swift

Question

Assume I receive data in some JSON which is then parsed to dictionary using a native tool. Some of those values are numbers and naturally I will need to parse them, cast them into what I need in the application.
But the transition from Any to an actual number such as Float, Int, Double seems to be a bit messy. For instance if I expect a double but at some point server returns an integer my code will fail using:
let doubleValue = dictionary["key"] as! Double
So this will work when the item is 1.3 but will fail for 1. To use a bit more concrete example we can use the following:
let myDictionary: [String: Any] = [
"myNumber_int" : 1,
"myNumber_float" : Float(1),
"myNumber_cgFloat" : CGFloat(1),
"myNumber_double" : 1.0
]
let numberInt1 = myDictionary["myNumber_int"] as? Int // 1
let numberInt2 = myDictionary["myNumber_int"] as? Float // nil
let numberInt3 = myDictionary["myNumber_int"] as? CGFloat // nil
let numberInt4 = myDictionary["myNumber_int"] as? Double // nil
let numberFloat1 = myDictionary["myNumber_float"] as? Int // nil
let numberFloat2 = myDictionary["myNumber_float"] as? Float // 1
let numberFloat3 = myDictionary["myNumber_float"] as? CGFloat // nil
let numberFloat4 = myDictionary["myNumber_float"] as? Double // nil
let numberCGFloat1 = myDictionary["myNumber_cgFloat"] as? Int // nil
let numberCGFloat2 = myDictionary["myNumber_cgFloat"] as? Float // nil
let numberCGFloat3 = myDictionary["myNumber_cgFloat"] as? CGFloat // 1
let numberCGFloat4 = myDictionary["myNumber_cgFloat"] as? Double // nil
let numberDouble1 = myDictionary["myNumber_double"] as? Int // nil
let numberDouble2 = myDictionary["myNumber_double"] as? Float // nil
let numberDouble3 = myDictionary["myNumber_double"] as? CGFloat // nil
let numberDouble4 = myDictionary["myNumber_double"] as? Double // 1
So for each type only 1 cast will actually work which is... well I would at least expect that CGFloat will be able to cast directly to Double or Float...
So my solution is using NSNumber:
let myNumbers: [CGFloat] = [
CGFloat((myDictionary["myNumber_int"] as? NSNumber)?.floatValue ?? 0.0),
CGFloat((myDictionary["myNumber_float"] as? NSNumber)?.floatValue ?? 0.0),
CGFloat((myDictionary["myNumber_cgFloat"] as? NSNumber)?.floatValue ?? 0.0),
CGFloat((myDictionary["myNumber_double"] as? NSNumber)?.floatValue ?? 0.0),
] // [1,1,1,1]
This naturally works but the code is pretty ugly for something as simple as this. But putting the code "ugliness" aside; can we not do similar without using Next Step? I mean NSNumber for something as seemingly trivial as this? I am missing something very obvious here, right?

Answer 1

Try like this:-
if let data = myDictionary as? [String: AnyObject] {
let myNumber = data["myNumber_int"] as? Int
}