Optionals: Nil

Var serverResponseCode: Int? = 404
// serverResponseCode contains an actual Int value of 404
serverResponseCode = nil
// serverResponseCode now contains no value

Var surveyAnswer: String?
// surveyAnswer is automatically set to nil

It’s the absence of a value of a certain type.

Additional information

• You set an optional variable to a valueless state by assigning it the special value nil.
• If you define an optional variable without providing a default value, the variable is automatically set to nil for you.