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Swiftのmapからその次へ
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oyuk
August 04, 2016
Programming
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Swiftのmapからその次へ
oyuk
August 04, 2016
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Transcript
Swiftͷmap͔Βͦͷ࣍ 2016/08/04 oyuk(@oydku)
ࣗݾհ • oyuk(@oydku) • iosΞϓϦΤϯδχΞ!
Swiftͷmap map͕͑ΔͭΒ͍͔ͭ͋͘ΔΑͶ • Optional (Enum) • Array (CollectionType) • ObservableType
(RxSwift) ଞʹ͔͋ͬͨͶɻ͋ͬͨΒڭ͑ͯ
mapͷఆٛΛݟΔ Optional func map<U>(@noescape f: (Wrapped) throws -> U) rethrows
-> U? Array func map<T>(@noescape transform: (Self.Generator.Element) throws -> T) rethrows -> [T] ObservableType public func map<R>(selector: Self.E throws -> R) -> RxSwift.Observable<R>
ڞ௨͋ΔΑͶ!
͍͍ͩͨ͜Μͳײ͡ func map<U>(f:T -> U) -> ͋Δ<U>
͍͍ͩͨ͜Μͳײ͡ func map<U>(f:T -> U) -> ͋Δ<U> Optional func map<U>(@noescape
f: (Wrapped) throws -> U) rethrows -> U? • Wrapped->UͷؔΛWrappedʹద༻ͯ͠U?Λฦ͢ • ͋Δ<U>͜͜ͰU?
͍͍ͩͨ͜Μͳײ͡ func map<U>(f:T -> U) -> ͋Δ<U> Array func map<T>(@noescape
transform: (Self.Generator.Element) throws -> T) rethrows -> [T] • Self.Generator.Element->TͷؔΛ Self.Generator.Elementʹద༻ͯ͠[T]Λฦ͢ • ͋Δ<U>͜͜Ͱ[U]
͍͍ͩͨ͜Μͳײ͡ func map<U>(f:T -> U) -> ͋Δ<U> ObservableType public func
map<R>(selector: Self.E throws -> R) -> RxSwift.Observable<R> • Self.E->RͷؔΛSelf.Eʹద༻ͯ͠ RxSwift.Observable<R>Λฦ͢ • ͋Δ<U>͜͜ͰRxSwift.Observable<R>
Μʁ
Ͳͷmapಉ͡ʢ͖ͬ͞ݴͬͨʣ func map<U>(f:T -> U) -> ͋Δ<U> • ͋Δ<T>ʹؔ(T->U)Λద༻ͯ͋͠Δ<U>Λฦ͢
۩ମతʹ func map<String>(f:Int -> String) -> Optional<String> Optional let o:Optional<String>
= Optional<Int>(1).map{String($0)}
۩ମతʹ func map<String>(f:Int -> String) -> Array<String> Array let a:Array<String>
= Array(arrayLiteral: 1,2,3).map {String($0)}
۩ମతʹ func map<String>(f:Int -> String) -> Observable<String> ObservableType let o:Observable<String>
= Observable.just(1).map{String($0)}
ΈΜͳಉͩ͡Ͷʢ͖ͬ͞ݴͬͨʣ let a:͋Δ<U> = ͋Δ<T>.map{U($0)} • ͋Δ͕ • Optional •
Array • Observable ʹͳΔΘ͚Ͱ͢ͳ
͋ΔͬͯԿʁ
Functor • શମΛҠͤΔͷΛද͢ • ؔखͱ͍͏Β͍͠ • ശʹྫ͑ΒΕΔࣄ͕͋Δ Πϝʔδ let a:Functor<U>
= Functor<T>.map{U($0)}
Functor let o:Optional<String> = Optional<Int>(1).map{String($0)} map͕͍ͯ͠Δ͜ͱ 1. Optional<Int>ͱ͍͏ശͷதΛऔΓग़͠ɺ͜ΕΛ$0ͱ͢ Δɻ 2.
$0ΛStringʹΩϟετ 3. $0ΛOptional<String>ͱ͍͏ശʹೖΕͯฦ͢
Functor let a:Array<String> = Array(arrayLiteral: 1,2,3).map {String($0)} map͕͍ͯ͠Δ͜ͱ 1. Array<Int>ͱ͍͏ശͷதΛऔΓग़͠ɺ͜ΕΛ$0ͱ͢Δɻ
2. $0ʢ֤ཁૉʣΛStringʹΩϟετ 3. $0ΛArray<String>ͱ͍͏ശʹೖΕͯฦ͢
Functor let o:Observable<String> = Observable.just(1).map{String($0)} map͕͍ͯ͠Δ͜ͱ 1. Observable<Int>ͱ͍͏ശͷதΛऔΓग़͠ɺ͜ΕΛ$0ͱ͢ Δɻ 2.
$0ΛStringʹΩϟετ 3. $0ΛObservable<String>ͱ͍͏ശʹೖΕͯฦ͢
·ͱΊ • mapͷഎޙʹFunctorͱ͍͏֓೦͕͋Δ • FunctorશମΛҠͤΔΛ͋ΒΘ͢ • ࠓճͷྫͰOptional,Array,Observable • શମΛҠ͢ಈ࡞͕mapͰ͋Δ