enum Optional<Wrapped> A type that can represent either a Wrapped value or nil, the absence of a value. Inheritance CustomDebugStringConvertible, NilLiteralConvertible, _Reflectable View Protocol Hierarchy → Import import Swift Cases case None case Some(Wrapped) Initializers init() Construct a nil instance. Declaration init() init(_:) Construct a non-nil instance that stores some. Declaration init(_ some: Wrapped) init(nilLiteral:) Create an instance initialized with nil. Declaration init(nilLiteral: ()) Instance Variables var debugDescription: String A textual representation of self, suitable for debugging. Declaration var debugDescription: String { get } Instance Methods func flatMap(_:) Returns nil if self is nil, f(self!) otherwise. Declaration func flatMap<U>(@noescape f: (Wrapped) throws -> U?) rethrows -> U? func map(_:) If self == nil, returns nil. Otherwise, returns f(self!). Declaration func map<U>(@noescape f: (Wrapped) throws -> U) rethrows -> U?