swift How to cast from Int? to String

Question

In Swift, i cant cast Int to String by:

var iString:Int = 100
var strString = String(iString)

But my variable in Int? , there for error:

Answer 1

If you need a one-liner it can be achieved by:

let x: Int? = 10
x.flatMap { String($0) } // produces "10"
let y: Int? = nil
y.flatMap { String($0) } // produces nil

if you need a default value, you can simply go with

(y.flatMap { String($0) }) ?? ""

EDIT:

Even better without curly brackets:

y.flatMap(String.init)

Apple's flatMap(_:) Documentation

Answer 2

Sonrobby, I believe that "Int?" means an optional int. Basically, by my understanding, needs to be unwrapped.

So doing the following works fine:

let y: Int? = 42
let c = String(y!)

That "!" unwraps the variable. Hope this helps!

As rakeshbs mentioned, make sure the variable won't be nill.

Answer 3

For preventing unsafe optional unwraps I use it like below as suggested by @AntiStrike12,

 if let theString = someVariableThatIsAnInt  {        
    theStringValue = String(theString!))
 }

Answer 4

Swift 3:

var iString:Int = 100
var strString = String(iString)
extension String {
    init(_ value:Int){/*Brings back String() casting which was removed in swift 3*/
        self.init(describing:value)
    }
}

This avoids littering your code with the verbose: String(describing:iString)

Bonus: Add similar init methods for commonly used types such as: Bool, CGFloat etc.

Answer 5

Crude perhaps, but you could just do:

let int100 = 100
println(int100.description) //Prints 100