Ordering and Ordered

How do you sort out your class instances in Scala? There are two useful traits for sorting: Ordered and Ordering. This presentation focuses on how to use these traits in the most efficient manner.

Transcript

1. Ordered & Ordering Seiya Izumi
2. About Me • Seiya Izumi (@sy_izumi) • Go ͱ Scala ͕ϝΠϯ • ࠷ۙͷϚΠϒʔϜ͸ Vape Ͱ͢
3. Ordered ͱ Ordering ʹ͍ͭͯݟ͚ͭͨ͜ͱΛ ࿩͠·͢
4. Case Class Λιʔτ͍ͨ͠!
5. Ordered τϨΠτ
6. Ordered τϨΠτ • compareϝιουΛ࣮૷͢Δ͜ͱͰ “<“ ΍ “>” ͳͲͷൺֱͷΦϖϨʔλ͕࢖͑ΔΑ͏ʹ ͳΔ
7. ͕ͩ… • ൺֱΛ͢ΔͨΊʹ೚ҙͷΫϥεʹຖճ Ordered τϨΠτΛϛΫεΠϯ͠ͳ͍ͱ͍͚ͳ͍ͷ ͔…? • ఆ͕ٛॻ͖׵͑ΒΕͳ͍ࣄ৘͕͋Δͱ͖͸໽հ ͩͳ • ଞʹ΋΍Γํ͸ͳ͍ͷ͔
8. Ordering τϨΠτ
9. Ordering τϨΠτ
10. Ordering τϨΠτ • ೚ҙͷΫϥεͷू߹ʹର͢Δൺֱͷετϥς δΛ༩͑Δ͜ͱ͕Ͱ͖Δͧ
11. SortingΛݟͯΈΔ ͜Ε͸ Context Bound ͷ༧ײ
12. ͱ͍͏͜ͱ͸implicitʹͰ͖Δ
13. ΋ͬͱ Ordering ΛݟͯΈΔ
14. Optionͷൺֱ΋༻ҙ͞ΕͯΔ ͜Μͳײ͡ͰimplicitΛ࢖͍ͬͯΖΜͳιʔτ͕༧Ί༻ҙ͞Ε͍ͯΔ
15. ோΊ͍ͯΔͱ͜ΜͳίʔυΛൃݟ Ͳ͏΍ΒIterableͷฒͼସ͑ϩδοΫͬΆ͍͜ͱ͸Θ͔Δ
16. ͜͏͍͏ͷ͕ΠέΔΜͩΖ͏͔
17. ͜͏͍͏ͷ͕ΠέΔΜͩΖ͏͔ ίϯύΠϧΤϥʔ
18. ·ͨผͷఆٛΛൃݟ
19. ·ͨผͷఆٛΛൃݟ Seq্͕ݶڥքʹͳͬͯΔ!
20. ·ͨผͷఆٛΛൃݟ ͳΔ΄Ͳ Implicits ΛΠϯϙʔτ͢Ε͹͍͍ͷ͔
21. ͜Ε͸Πέͨʂ
22. ͡Ό͋͜Ε͸ͳΜͳͷ͔…
23. ྺ࢙Λඥղ͘
24. GithubΛݟͯΈΑ͏
25. ͦΕͬΆ͍΋ͷΛൃݟ
26. implicit def Iterable ͷ΄͏ͷ࣮૷͸ Iterable ʹର͚ͯͩ͠ Ordering Λద༻͍ͯͯ͠ɺαϒΫϥεʹ͸ద༻͍ͯ͠ͳ͍ͷ͕ ໰୊ͩɻ͔ͩΒ implicit ϝιου͕2ͭଘࡏ͍ͯ͠ΔΜͰ͸ͳ͍ ͔ͱࢥ͏ɻԿͰ2ͭඞཁͳͷ͔͸஌ΒΜ͚Ͳɻ
27. ͪΐͬͱߟ͑ͯΈ͚ͨͲ Iterable ͸ཁૉॱংͷ Ұ؏ੑΛอূ͠ͳ͍͔Β implicit def Iterable ͷ ΄͏͸ফͯ͠͠·͏ͷ͕ଥ౰͡Όͳ͍͔ͳʁ
28. ͦͷͱ͓Γͩʂ ফͦ͏ ͦ͏ͩͶɻͦͬͪ͸ফͯ͠ Seq ʹରԠ͢Δ΄͏͚ͩ࢒ͦ͏
29. ͱ͍͏͜ͱͰ 2.13 ͔Β͸ Seq ͱ SortedSet ͷ ΈΛ্ݶڥքͱ͢ΔΑ͏ʹ
30. Deprecated ʹͳͬͨ Iterable ͘Μ
31. ୭͕ͳΜͷܦҢͰ ௥Ճͨ͠ͷ͔
32. ෼͔Βͳ͍
33. ίʔυίϝϯτͬͯ େࣄͰ͢Ͷ…
34. 完