Parsing unsigned integer from JSON dictionary in Swift -

i'm trying write code parse json value (which string or integer in json) optional unsigned integer (i.e. uint?), being tolerant value being missing or not being parsable - want result have value if source data contains legitimate positive value:

convenience init(jsondictionary: nsdictionary) {     ...     var numlikesunsigned: uint?     if let likesobj: anyobject = jsondictionary.valueforkey("likecount") {         let likes = "\(likesobj)"         if let numlikessigned = likes.toint() {             numlikesunsigned = uint(numlikessigned)         }     }     self.init(numlikesunsigned) } 

this seems incredibly unwieldy. hard?

you can this:

var numlikesunsigned = (jsondictionary["likecount"]?.integervalue).map { uint($0) } 

---

since nsstring , nsnumber both has integervalue property, can access .integervalue no matter type that.

let dict:nsdictionary = ["foo":42 , "bar":"42"]  let foo = dict["foo"]?.integervalue // -> 42 int? let bar = dict["bar"]?.integervalue // -> 42 int? 

and, optional has .map method:

/// if `self == nil`, returns `nil`.  otherwise, returns `f(self!)`. func map<u>(f: (t) -> u) -> u? 

you can:

let intval:int? = 42 let uintval = intval.map { uint($0) } // 42 uint? 

instead of:

let intval:int? = 42  let uintval:uint? if let ival = intval {     uintval = uint(ival) }