How to determine the type of a variable in Swift

Question

Is there a function to determine the variable type in Swift? I presume there might be something like like type() in Python.

I\'d like a way to judge if

Answer 1

It is possible to do so, though it's not necessarily that easy nor useful:

func getClassName(obj : AnyObject) -> String
{
    let objectClass : AnyClass! = object_getClass(obj)
    let className = objectClass.description()

    return className
}

let swiftArray = [1, 2, 3]
let swiftDictionary = ["Name": "John Doe"]
let cocoaArray : NSArray = [10, 20, 30]
var mutableCocoaArray = NSMutableArray()

println(getClassName(swiftArray))
println(getClassName(swiftDictionary))
println(getClassName(cocoaArray))
println(getClassName(mutableCocoaArray))

Output:

_TtCSs22ContiguousArrayStorage00007F88D052EF58
__NSDictionaryM
__NSArrayI
__NSArrayM

You are better of using the is and as keywords in Swift. Many foundation classes use class clusters (as you can see with __NSArrayI (immutable) and __NSArrayM (mutable).

Notice the interesting behavior. The swiftArray defaults to using a Swift Array while the swiftDictionary defaulted to NSMutableDictionary. With this kind of behavior I would not really rely on anything being a certain type (check first).