Equatable, Comparable and Hashable

Transcript

1. Equatable / Comparable /
   Hashable
   Λ׬શʹཧղ͢Δ
   @S_Shimotori
   Otemachi.swift x Kyobashi.swift #01
   

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2. ͩΕ
   • @S_Shimotori·ͨ͸@S_Shimotori_pub
   • ֶੜ
   • DroidKaigi2016-2018ӡӦϝϯόʔ
   

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3. iOSDCʹొஃ͠·͢
   • #1349ʮARC vs. GCʁARC in GCʁʯ
   • 5෼ͰGCͷ࿩Λ͠·͢
   • ݫ͍͠
   • Reject͞Εͨ΍ͭ΋ద౰ʹڙཆ͢Δͭ΋Γ
   • ςετ
   • ԋࢉࢠ
   • Ͳ͜Ͱʁ
   

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4. Equatable
   Comparable
   Hashable
   

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5. ͓͞Β͍
   • Equatable
   • ౳͍͔͠Ͳ͏͔ൺֱͰ͖Δ
   • Comparable
   • ؔ܎ԋࢉࢠͰൺֱͰ͖Δ
   • ͍͍ͪͪൺֱ༻ͷؔ਺Λ༻ҙ͠ͳͯ͘΋ιʔτͰ͖Δ
   • Hashable
   • ϋογϡ஋Λ࡞ΕΔ
   • Map/DictionaryͷΩʔʹͳΕΔ
   • Java͸ComparableͷΈinterfaceͰ࢒Γ͸class Objectʹੜ͑ͯΔ
   • Python͸duck typing
   

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6. SwiftͰ͸:
   

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7. EquatableͱΏ͔͍ͳ஥ؒͨͪ(Ұ෦লུ)
   &RVBUBCMF
   $PNQBSBCMF )BTIBCMF /VNFSJD 4FU"MHFCSB
   4USJEFBCMF
   4USJOH1SPUPDPM 3FGFSFODF$POWFSUJCMF
   Foundation಺ͷࢀরܕ΁ଓ͘ɻ
   String͕ଓ͘ɻ
   1࣍ݩͷ࿈ଓతͳ஋ɻ
   ਺஋΍UnsafePointer͕ଓ͘ɻ
   ೋ߲ࢉज़ԋࢉɻ Set͕ଓ͘ɻ
   • ΋ͬͱ΋ਓؾͳProtocolͷ1ͭ
   • ͳʹΑΓଘࡏײ͕େ͖͍ɺେ͖͗͢Δ
   • Equatable.swiftʹ͸ͪΌ͔ͬΓಉҰ൑ఆͷ࣮૷΋͍Δ
   

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8. protocol Equatable
   

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9. ͱΓ͋͑ͣ
   == Λ࣮૷͢Ε͹OKʂ
   ❌
   

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10. protocol Equatableͷཁ݅
    • ୅ସՄೳੑ
    • ൓ࣹੑ
    • ରশੑ
    • ਪҠੑ
    • a == b ͕ਅͳΒ not a != b ͕ਅ
    • ͜ͷ͏ͪEquatable͔ΒϑΥϩʔ͕ೖΔͷ͸࠷ޙ͚ͩʂ
    • ҙਤతʹΦʔόʔϥΠυ͠ͳ͍ݶΓ==ͷٯͷ݁ՌΛฦ͢
    

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11. OptionalͱEquatableͷؔ܎
    • Optional͸EquatableͰ͸ͳ͍
    • Ͱ΋is Equatableͷ݁Ռ͸த਎ʹґଘ͢Δ
    • Ͱ΋ผͰԋࢉࢠ͕࣮૷͞Ε͍ͯΔͷͰnilͱͷൺֱ͸Մೳ
    

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12. protocol Comparable
    

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13. ద౰ʹ < Λ࣮૷͓͚ͯ͠͹
    ͳΜͱ͔ͳΔ΍ͭ
    ❌
    

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14. protocol Comparableͷ໾ׂͱཁ݅
    • ܕʹࣗવॱং෇͚Λ༩͑Δ
    • σϑΥϧτͷιʔτํ๏ΛܾΊΔͱ͍͏͜ͱ
    • Swift͸ؔ܎ԋࢉࢠͰදݱ͍ͯ͠ΔͷͰEquatable͕ඞਢ
    • ࡶʹ࣮૷͠ͳ͍ݶΓ͸Equatableͱໃ६͠ͳ͍
    • ࡶʹ࣮૷͠ͳ͍ݶΓ͸ < = > ͷͲΕ͔1͚͕ͭͩtrueʹͳΔ
    • strict total orderingͱݺ͹ΕΔੑ࣭Λຬͨ͞ͳ͚Ε͹ͳΒͳ͍
    • ʮ͖ͬͪΓϧʔϧΛܾΊͯશһҰྻʹฒ΂ͳ͍ͱͩΊʯ
    • ුಈখ਺఺਺ͳͲͰྫ֎͕ೝΊΒΕΔ৔߹͕͋Δ
    

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15. sort͸2छྨ
    • Ҿ਺ͳ͠ͷsort / sorted
    • ࣗવॱং෇͚ʹैͬͯιʔτ͢Δ
    • ͭ·Γཁૉ͕ComparableͰͳ͚Ε͹ͳΒͳ͍
    • Ҿ਺ΛऔΔsort / sorted
    • ର৅ίϨΫγϣϯ಺ͷΈͰ௨༻͢Δॱং෇͚Ͱιʔτ͢Δ
    • ཁૉ͕ComparableͰͳͯ͘΋͍͍
    • strict weak orderingͳॱং෇͚͕ڐ͞ΕΔ
    • Comparableͱͷҧ͍͸ൺֱෆೳ͕ڐ͞ΕΔ͜ͱ
    • ͲͪΒ΋࠷ޙ͸ॱং෇͚ʹैͬͯΠϯτϩιʔτ͞ΕΔ
    

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16. protocol Hashable
    

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17. ͱΓ͋͑ͣ
    ϋογϡ஋Λग़͓͚ͯ͠͹OKʂ
    ❌
    

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18. protocol Hashable
    • ϋογϡΛ࣮૷͢Δͱ͖ͷΑ͋͘Δ஫ҙ
    • ޓ͍ʹಉ஋ͳΒϋογϡ஋΋౳͘͠ͳ͚Ε͹ͳΒͳ͍
    • ٯ͸੒ཱ͠ͳͯ͘΋Α͔ͬͨΓ͢Δ
    • SwiftͰ͸EquatableඞਢͳͷͰ࣮૷Λ๨ΕΔ͜ͱ͸ͳ͍͸ͣ
    • ϧʔϧʹଇͬͯͪΌΜͱ࣮૷͢Δ͜ͱʂ
    

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19. Ҏ্ʂ
    

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20. ͓·͚
    

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21. assertEqual
    

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22. assertEqualʹ͸ݴޠͷݸੑ͕ग़Δ
    • Javaʹ͸ࢀরܕ༻ͱϓϦϛςΟϒܕ༻͕ͦΕͧΕ༻ҙ͞Ε͍ͯΔ
    • Pythonʹ͸1छྨ͔͠ͳ͍
    • Objective-C͸ΦϒδΣΫτ༻ͱεΧϥ༻͕༻ҙ͞Ε͍ͯΔ
    • Swift͸NonNull༻ͱNullable༻͕༻ҙ͞Ε͍ͯΔ
    • ࢀরܕͱ஋ܕͰͷ۠ผͰ͸ͳ͍
    • ͜ͷ2ͭ΋΄ͱΜͲҧ͍͕ͳ͍ɺ࣮࣭1छྨɻ
    

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23. ·ͱΊ
    

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24. ·ͱΊ
    • Equatable / Comparable / Hashableʹ͸ϧʔϧ͕͋Δ
    • ޓ͍ͷؔ܎ੑ͸protocolͷܧঝͰදݱ͞Ε͍ͯΔ͕ɺ
    ϧʔϧʹଇ͍ͬͯΔ͔Ͳ͏͔͸ݟͯ͘Εͳ͍
    ਖ਼࣮͘͠૷͠·͠ΐ͏ʂ
    ཧ૝Λݴ͑͹ͦͷςετ΋ཉ͘͠ͳ͍ʁ
    

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