The Optional type is an enumeration with two cases. .none is equivalent to the nil literal. .some(Wrapped) stores a wrapped value. You must unwrap the value of an Optional before you can use it.

Common ways to unwrap an Optional safely are:

  • Optional Binding: if let ...
  • Optional Chaining: if one?.two?...
  • Nil-Coalescing: let a: Int = optional ?? 0
  • Unconditional Unwrapping: let number = Int("42")!

Another method to safely unwrap an Optional is a combination of extension and Nil-Coalescing. Here is a simple extension which allows us to safely unwrap String:

extension Optional where Wrapped == String {
    var unwrapped: String {
        return self ?? ""

let a: String? 

if a.unwrapped.isEmpty == 0 {
    print("Oh, no! It's empty!")

Further reading