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

Optional Int -> Optional String:

If x: Int? (or Double? - doesn't matter)

var s = x.map({String($0)})

This will return String?

To get a String you can use :

var t = s ?? ""

Answer 2

You can try this to convert Int? to string

let myString : String = "42"
let x : Int? = myString.toInt()

let newString = "\(x ?? 0)"
print(newString)        // if x is nil then optional value will be "0"

Answer 3

Hope this helps

var a = 50
var str = String(describing: a)

Answer 4

You need to "unwrap" your optional in order to get to the real value inside of it as described here. You unwrap an option with "!". So, in your example, the code would be:

let myString : String = "42"
let x : Int? = myString.toInt()

if (x != null) {
    // Successfully converted String to Int
    // Convert x (an optional) to string by unwrapping
    let myNewString = String(x!)
}

Or within that conditional, you could use string interpolation:

let myNewString = "\(x!)" // does the same thing as String(x!)

Answer 5

You can use string interpolation.

let x = 100
let str = "\(x)"

if x is an optional you can use optional binding

var str = ""
if let v = x {
   str = "\(v)"
}
println(str)

if you are sure that x will never be nil, you can do a forced unwrapping on an optional value.

var str = "\(x!)"

In a single statement you can try this

let str = x != nil ? "\(x!)" : ""

Based on @RealMae's comment, you can further shorten this code using the nil coalescing operator (??)

let str = x ?? ""

Answer 6

I like to create small extensions for this:

extension Int {
    var stringValue:String {
        return "\(self)"
    }
}

This makes it possible to call optional ints, without having to unwrap and think about nil values:

var string = optionalInt?.stringValue