Initializer

init(_:)

Creates a property that can save and restore an Optional double.

Declaration 宣言

init(_ key: String) where Value == Optional<Double>
Available when Value conforms to ExpressibleByNilLiteral. ValueExpressibleByNilLiteralに準拠する場合に利用可能です。

Parameters パラメータ

key

a key used to save and restore the value.

Discussion 議論

Defaults to nil if there is no restored value

See Also 参照

Storing an Optional Value