Upgrade to Pro
— share decks privately, control downloads, hide ads and more …
Speaker Deck
Features
Speaker Deck
PRO
Sign in
Sign up for free
Search
Search
いつか役にたつかもしれないコレクション周りの5つのこと
Search
RyotaMurohoshi
July 05, 2016
Programming
2
760
いつか役にたつかもしれないコレクション周りの5つのこと
2016//07/05(火)に開催された「Kotlin 勉強会 #1 - 初めての Kotlin」で発表した資料です
http://connpass.com/event/33584/
RyotaMurohoshi
July 05, 2016
Tweet
Share
More Decks by RyotaMurohoshi
See All by RyotaMurohoshi
Tilemapのアップデートについて
ryotamurohoshi
0
24
Unityの合同同人誌や合同商業誌を書いてる僕は感想やレビューや評価が欲しい
ryotamurohoshi
0
530
Unity 2021.1での Unityパッケージの名称変更について
ryotamurohoshi
0
710
Odin Validationはいいぞ!
ryotamurohoshi
2
960
Tilemapはいいぞ!2020 〜すごいぞ、プロジェクト専用拡張Brush〜
ryotamurohoshi
0
2.4k
Unityでも、新しいC#
ryotamurohoshi
0
1.3k
Riderはいいぞ!
ryotamurohoshi
1
3.5k
Riderのススメ〜俺はRiderここが好き〜
ryotamurohoshi
1
2.4k
Unity開発者に伝えたい.NETのこと
ryotamurohoshi
4
37k
Other Decks in Programming
See All in Programming
AI Agent 時代のソフトウェア開発を支える AWS Cloud Development Kit (CDK)
konokenj
5
650
ISUCON研修おかわり会 講義スライド
arfes0e2b3c
1
460
LT 2025-06-30: プロダクトエンジニアの役割
yamamotok
0
810
Agentic Coding: The Future of Software Development with Agents
mitsuhiko
0
120
Quand Symfony, ApiPlatform, OpenAI et LangChain s'allient pour exploiter vos PDF : de la théorie à la production…
ahmedbhs123
0
210
Startups on Rails in Past, Present and Future–Irina Nazarova, RailsConf 2025
irinanazarova
0
200
イベントストーミング図からコードへの変換手順 / Procedure for Converting Event Storming Diagrams to Code
nrslib
2
970
The Evolution of Enterprise Java with Jakarta EE 11 and Beyond
ivargrimstad
0
180
AI時代のソフトウェア開発を考える(2025/07版) / Agentic Software Engineering Findy 2025-07 Edition
twada
PRO
97
34k
VS Code Update for GitHub Copilot
74th
2
670
脱Riverpod?fqueryで考える、TanStack Queryライクなアーキテクチャの可能性
ostk0069
0
340
AIと”コードの評価関数”を共有する / Share the "code evaluation function" with AI
euglena1215
1
180
Featured
See All Featured
Making Projects Easy
brettharned
116
6.3k
Scaling GitHub
holman
460
140k
Designing for humans not robots
tammielis
253
25k
GraphQLの誤解/rethinking-graphql
sonatard
71
11k
KATA
mclloyd
30
14k
Chrome DevTools: State of the Union 2024 - Debugging React & Beyond
addyosmani
7
740
Building a Modern Day E-commerce SEO Strategy
aleyda
42
7.4k
The MySQL Ecosystem @ GitHub 2015
samlambert
251
13k
For a Future-Friendly Web
brad_frost
179
9.8k
Mobile First: as difficult as doing things right
swwweet
223
9.7k
How To Stay Up To Date on Web Technology
chriscoyier
790
250k
Easily Structure & Communicate Ideas using Wireframe
afnizarnur
194
16k
Transcript
ผʹܶతʹมΘΒͳ͍͚ΕͲ ͍͔ͭʹ͔ͨͭ͠Εͳ͍ ίϨΫγϣϯपΓͷ5ͭͷ͜ͱ @RyotaMurohoshi 2016/07/05(Ր)*͡ΊͯͷKotlin
ͦͷ1 ঢ়گʹԠͯ͡SequenceΛ͏͖ͳ݅
100000ߦͷJSON'LinesϑΝΠϧ ͜ΕΛ1ߦͣͭdataΫϥεͷΦϒδΣΫτʹม͠ ͋Δ݅Λຬͨ͢ΦϒδΣΫτΛ ࠷ॳ͔Β10͚݅ͩ֬ೝද͍ࣔͨ͠
List<T>ͷ߹
val lineList: List<String> = File("data.jsonlines").readLines() val result = lineList .map
{ convertToData(it) } .filter { filterData(it) } .take(10) for (it in result) { println(it) }
࠷ޙ·ͰϑΝΠϧΛಡΜͰ͠·͏
Sequence<T>ͷ߹
val result: List<PersonData> = File("data.jsonlines") .useLines { lineSequences: Sequence<String> ->
lineSequences .map { convertToData(it) } .filter { filterData(it) } .take(10) .toList() } for (it in result) { println(it) }
ϑΝΠϧΛ࠷ޙ·Ͱಡ·ͳ͍
ৄ͘͜͠ͷࢿྉͰʂ h"ps:/ /speakerdeck.com/ryotamurohoshi/sequencefalsehua8kotlin8dot8sequences8dot8sequence
ͦͷ2 ཁૉ͕ۭͷ࣌ͷaverageϝιου͕ 0.0Λฦͯ͠͠·͏݅
averageϝιουͱʁ List<Int>ͱ͔ͷฏۉܭࢉϝιου
͡Ό͋ɺཁૉ͕ۭͷ࣌ʁ
·͔͞ͷ0.0!
ͳͥͩʂʁ
͜Ε͡Όܭࢉ݁Ռ͕0.0ͩͬͨͷ͔ɺ ཁૉ͕ۭ͔ͩΒ0.0ͬͨͷ͔ ۠ผԽ͔ͭͳ͍ʂʂʂ
ͦͦͳͥDouble?ܕʹ͠ͳ͔ͬͨͷ͔ʁ maxminInt?Λฦ͢ͷʹʂ ͘͠ྫ֎Λ͛ͯཉ͍͠
ͦͷ3 Ωʔ͕ॏෳͨ͠ࡍͷassociateܥϝιου͕ɺ ྫ֎Λ͛ͳ͍݅
associateܥͷϝιουͱʁ Listͱ͔͔ΒMapΛͭ͘Δϝιου
data class Person( val id: Long,ɹval name: String, val teamId:
Long) // ॏෳidͷPersonଘࡏ͠ͳ͍ // ಉ͡teamIdΛ࣋ͭPersonଘࡏ͠͏Δ val personList : List<Person>ɹ= loadPersonList() // id͕ॏෳ͠ͳ͍ͷͰແ͠ val personMap : Map<Long, Person> = personList.associateBy { it.id } // ʲʂʂʂʳಉ͡teamIdΛͭཁૉ͕personListʹଘࡏ͠͏Δʂʂʂʂʂ val teamMap : Map<Long, Person> = personList.associateBy { it.teamId }
͠Key͕ॏෳͨ͠Βʁ
ޙউʂ ͋ͱ͕ͪ:ޙΖͷཁૉͰ্ॻ͖
ݸਓతʹྫ֎Λ͛ͯཉ͍͠
ͦͦMapΛͭ͘ͷͰ͋ΕɺKeyҰҙͳͷͳͣ Key͕ॏෳ͢ΔͷΛఆ͢ΔͳΒɺgroupByΛ͏͖
ಥવͷએ
C#ͷLINQޓͷϥΠϒϥϦ KotLinq࡞͍ͬͯ·͢ʂʂʂ h"ps:/ /github.com/RyotaMurohoshi/KotLinq
ࠓճͷTips KotLinqΛ࡞͍ͬͯΔࡍͷݟͰ͢
ͦͷ4 σϑΥϧτΠϯϙʔτ֦ுؔΛ ্ॻ͖Ͱ͖Δ݅
ࣗ࡞ϥΠϒϥϦKotLinqͷʹ takeͬͯϝιου͕͋Γ·͢ʂ
KotLinqͷtakeϝιου fun <TSource> Iterable<TSource>.take(count: Int): Sequence<TSource> = asSequence().take(count)
Μʁ
ඪ४ؔʹtakeͬͯ͋ͬͨΑ͏ͳ? fun <T> Iterable<T>.take(n: Int): List<T>
ඪ४ͰΠϯϙʔτͰ͖Δ֦ுؔ Λ্ॻ͖Ͱ͖Δ݅ʂ
ͦͷ5 ϝιουͷΦʔόʔϩʔυͱit͕ ૬ੑѱ͍݅ (͜Ε͋Μ·ΓίϨΫγϣϯؔͳ͍)
ࣹӨϝιου!ͱ!ΠϯσοΫε͖ࣹӨϝιουೋͭ࡞Γ͍ͨ // ࣹӨϝιου fun <TSource, TResult> Sequence<TSource> .select(selector: (TSource) ->
TResult): Sequence<TResult> // ΠϯσοΫε͖ࣹӨϝιου fun <TSource, TResult> Sequence<TSource> .select(selector: (TSource, Int) -> TResult): Sequence<TResult>
ࣹӨϝιου!ͱ!ΠϯσοΫε͖ࣹӨϝιου ҰҙʹܾΊΒΕͳ͍͔ΒίϯύΠϧΤϥʔ sequenceOf(1, 2, 3).select { it * 2 }
KotLinq(ͰɺΠϯσοΫε͖ࣹӨϝιουΛ ผ໊ʹ͠·ͨ͠ sequence.select { it * it }!ͱ͔͍ͨ͠͠
·ͱΊ • ঢ়گʹԠͯ͡SequenceΛ͏͖ͳ݅ • ཁૉ͕ۭͷ࣌ͷaverageϝιου͕0.0Λฦͯ͠͠·͏݅ • Ωʔ͕ॏෳͨ͠ࡍͷassociateܥϝιου͕ྫ֎Λ͛ͳ͍݅ • σϑΥϧτΠϯϙʔτ֦ுؔΛ্ॻ͖Ͱ͖Δ݅ •
ϝιουͷΦʔόʔϩʔυͱit͕૬ੑѱ͍݅
·ͱΊ KotLinqʹΛ