JavaScriptのコールバック関数を引数付きで実行する方法は、無名関数に包むこと。
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const p = console.log; const disp = arg => { p(arg); }; setTimeout(() => { const str = 'delay : ' + 13; disp(str); }, 13); |
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delay : 13 |
JavaScript
求人5社の言語別の求人数の各平均値を求めた
(data.csv)
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プログラミング言語,リクナビNext,DODA,パイザ,キャリコネ,Indeed HTML,117,256,283,1642,7643 JavaScript,104,380,889,2362,7093 PHP,248,722,866,3605,9319 Java,484,1729,990,5372,15893 Python,87,301,255,1606,3378 C++,1172,701,393,998,5897 C#,1172,669,552,882,6412 Swift,34,92,278,805,1129 Ruby,83,286,464,2200,3919 R,5,8,26,22,313 |
(Main.js)
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const main = () => { const p = console.log const fs = require('fs') class Agent { constructor(name, html, js, php, java, python, cp, cs, swift, ruby, r) { this.name = name this.html = Number(html) this.js = Number(js) this.php = Number(php) this.java = Number(java) this.python = Number(python) this.cp = Number(cp) this.cs = Number(cs) this.swift = Number(swift) this.ruby = Number(ruby) this.r = Number(r) this.updateShare() } calcSum() { return this.html + this.js + this.php + this.java + this.python + this.cp + this.cs + this.swift + this.ruby + this.r } updateShare() { const sum = this.calcSum() this.htmlShare = 100 * this.html / sum this.jsShare = 100 * this.js / sum this.phpShare = 100 * this.php / sum this.javaShare = 100 * this.java / sum this.pythonShare = 100 * this.python / sum this.cpShare = 100 * this.cp / sum this.csShare = 100 * this.cs / sum this.swiftShare = 100 * this.swift / sum this.rubyShare = 100 * this.ruby / sum this.rShare = 100 * this.r / sum } } const convertDataTo2dArray = data => { const a = [] data.split('\n').forEach(line => { a.push(line.split(',')) }) return a } const convert2dArrayToAgents = a => { const agents = {} agents.rnn = new Agent(a[0][1], a[1][1], a[2][1], a[3][1], a[4][1], a[5][1], a[6][1], a[7][1], a[8][1], a[9][1], a[10][1]) agents.doda = new Agent(a[0][2], a[1][2], a[2][2], a[3][2], a[4][2], a[5][2], a[6][2], a[7][2], a[8][2], a[9][2], a[10][2]) agents.paiza = new Agent(a[0][3], a[1][3], a[2][3], a[3][3], a[4][3], a[5][3], a[6][3], a[7][3], a[8][3], a[9][3], a[10][3]) agents.cc = new Agent(a[0][4], a[1][4], a[2][4], a[3][4], a[4][4], a[5][4], a[6][4], a[7][4], a[8][4], a[9][4], a[10][4]) agents.indeed = new Agent(a[0][5], a[1][5], a[2][5], a[3][5], a[4][5], a[5][5], a[6][5], a[7][5], a[8][5], a[9][5], a[10][5]) return agents } const calcHtmlShareAverage = agents => (agents.rnn.htmlShare + agents.doda.htmlShare + agents.paiza.htmlShare + agents.cc.htmlShare + agents.indeed.htmlShare) / 5 const calcJsShareAverage = agents => (agents.rnn.jsShare + agents.doda.jsShare + agents.paiza.jsShare + agents.cc.jsShare + agents.indeed.jsShare) / 5 const calcPhpShareAverage = agents => (agents.rnn.phpShare + agents.doda.phpShare + agents.paiza.phpShare + agents.cc.phpShare + agents.indeed.phpShare) / 5 const calcJavaShareAverage = agents => (agents.rnn.javaShare + agents.doda.javaShare + agents.paiza.javaShare + agents.cc.javaShare + agents.indeed.javaShare) / 5 const calcPythonShareAverage = agents => (agents.rnn.pythonShare + agents.doda.pythonShare + agents.paiza.pythonShare + agents.cc.pythonShare + agents.indeed.pythonShare) / 5 const calcCpShareAverage = agents => (agents.rnn.cpShare + agents.doda.cpShare + agents.paiza.cpShare + agents.cc.cpShare + agents.indeed.cpShare) / 5 const calcCsShareAverage = agents => (agents.rnn.csShare + agents.doda.csShare + agents.paiza.csShare + agents.cc.csShare + agents.indeed.csShare) / 5 const calcSwiftShareAverage = agents => (agents.rnn.swiftShare + agents.doda.swiftShare + agents.paiza.swiftShare + agents.cc.swiftShare + agents.indeed.swiftShare) / 5 const calcRubyShareAverage = agents => (agents.rnn.rubyShare + agents.doda.rubyShare + agents.paiza.rubyShare + agents.cc.rubyShare + agents.indeed.rubyShare) / 5 const calcRShareAverage = agents => (agents.rnn.rShare + agents.doda.rShare + agents.paiza.rShare + agents.cc.rShare + agents.indeed.rShare) / 5 const sub = () => { const d = fs.readFileSync("data.csv", {encoding: "utf-8"}) const a = convertDataTo2dArray(d) const o = convert2dArrayToAgents(a) p('HtmlShareAverage : ', calcHtmlShareAverage (o)) p('JsShareAverage : ', calcJsShareAverage (o)) p('PhpShareAverage : ', calcPhpShareAverage (o)) p('JavaShareAverage : ', calcJavaShareAverage (o)) p('PythonShareAverage : ', calcPythonShareAverage(o)) p('CpShareAverage : ', calcCpShareAverage (o)) p('CsShareAverage : ', calcCsShareAverage (o)) p('SwiftShareAverage : ', calcSwiftShareAverage (o)) p('RubyShareAverage : ', calcRubyShareAverage (o)) p('RShareAverage : ', calcRShareAverage (o)) } sub() } main() |
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HtmlShareAverage : 6.986354843278131 JsShareAverage : 10.378601229059685 PhpShareAverage : 14.44282913557401 JavaShareAverage : 24.16914753977421 PythonShareAverage : 5.442704295588216 CpShareAverage : 13.941919944259928 CsShareAverage : 14.503864909656471 SwiftShareAverage : 2.860625180852734 RubyShareAverage : 6.985042195338946 RShareAverage : 0.28891072661766853 |
クイックソートとバブルソートを両方やる
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'use strict' const main = () => { const p = console.log const getRandomInt = (min = 0, max = 9) => { const offset = Math.floor(Math.random() * (max - min + 1)) return min + offset } const getBlankArray = (size = 10) => { const a = [] for (let i = 0; i < size; i++) { a[i] = 0 } return a } const dispArrayList = a => { const len = a.length for (let i = 0; i < len; i++) { p(i + " => " + a[i]) } } const setRandomForArray = (a, min = 0, max = 9) => { const len = a.length for (let i = 0; i < len; i++) { a[i] = getRandomInt(min, max) } } const getPivot = (a, b, c) => { if (a < b) { if (b < c) { return b } else { return a < c ? c : a } } else { if (a < c) { return a } else { return b < c ? b : c } } } const swap = (a, left, right) => { const t = a[left] a[left] = a[right] a[right] = t } const quicksort = (a, left = 0, right = -1) => { if (right === -1) { right = a.length - 1 } if (right <= left) { return } let l = left let r = right const p = getPivot(a[l], a[l + 1], a[r]) while (true) { while (a[l] < p) { l++ } while (p < a[r]) { r-- } if (r <= l) { break } swap(a, l, r) l++ r-- } quicksort(a, left, l - 1) quicksort(a, r + 1, right) } const bubblesort = a => { const len = a.length for (let i = 0; i < len - 1; i++) { for (let j = i + 1; j < len; j++) { if (a[j] < a[i]) { swap(a, i, j) } } } } const getCloneArray = a => { const len = a.length const b = [] for (let i = 0; i < len; i++) { b[i] = a[i] } return b } const sub = () => { const a = getBlankArray(20) setRandomForArray(a) const b = getCloneArray(a) p("a : " + a) p("b : " + b) quicksort(a) bubblesort(b) p("a : " + a) p("b : " + b) } sub() } main() |
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a : 3,1,7,4,6,2,4,2,3,9,7,1,8,0,4,7,4,2,3,8 b : 3,1,7,4,6,2,4,2,3,9,7,1,8,0,4,7,4,2,3,8 a : 0,1,1,2,2,2,3,3,3,4,4,4,4,6,7,7,7,8,8,9 b : 0,1,1,2,2,2,3,3,3,4,4,4,4,6,7,7,7,8,8,9 |
JavaScriptでquicksort
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const main = () => { const p = console.log const getRandomInt = (min = 0, max = 9) => { const randomOffset = Math.floor(Math.random() * (max - min + 1)) return min + randomOffset } const dispArrayList = a => { a.forEach((v, k) => { p(k + " => " + v) }) } const getBlankArray = (len = 10) => { const a = [] for (let i = 0; i < len; i++) { a[i] = 0 } return a } const setRandomIntForArray = (a, min = 0, max = 9) => { const len = a.length for (let i = 0; i < len; i++) { a[i] = getRandomInt(min, max) } } const getPivot = (a, b, c) => { if (a < b) { if (b < c) { return b } else { return a < c ? c : a } } else { if (a < c) { return a } else { return b < c ? c : b } } } const swap = (a, l, r) => { const t = a[l] a[l] = a[r] a[r] = t } const quicksort = (a, left = 0, right = -1) => { if (right === -1) { right = a.length - 1 } if (right <= left) { return } let l = left let r = right const p = getPivot(a[l], a[l + 1], a[r]) while (true) { while (a[l] < p) { l++ } while (p < a[r]) { r-- } if (r <= l) { break; } swap(a, l, r) l++ r-- } quicksort(a, left, l - 1) quicksort(a, r + 1, right) } const sub = () => { const a = getBlankArray(30) setRandomIntForArray(a) p("ソート前", a) quicksort(a) p("ソート後", a) } sub() } main() |
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ソート前 [ 8, 2, 7, 5, 4, 8, 0, 1, 6, 7, 7, 3, 8, 0, 7, 9, 5, 0, 4, 4, 1, 1, 3, 5, 1, 8, 9, 1, 0, 8 ] ソート後 [ 0, 0, 0, 0, 1, 1, 1, 1, 1, 2, 3, 3, 4, 4, 4, 5, 5, 5, 6, 7, 7, 7, 7, 8, 8, 8, 8, 8, 9, 9 ] |
時間の昇順で指定したディレクトリのファイルパス一覧を取得する
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const fs = require('fs') const getFilePathListSortedByTimeStampAsc = dir => { const fileList = [] files = fs.readdirSync(dir) for (const file of files) { const filePath = dir + '/' + file const mtime = fs.statSync(filePath).mtime fileList.push({ filePath: filePath, mtime: mtime }) } return fileList .sort((a, b) => a.mtime - b.mtime) // ASC .map(file => file.filePath) } |
filterで引数の配列から偶数の要素に絞った新たな配列を得る
従来のforより短くかけることを認めざるを得ない
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'use strict' /* 引数の配列から偶数の要素に絞った新たな配列を得る */ const p = console.log const a = [-2, -1, 0, 1, 2, 3, 4, 5] p(a) /* for */ const getOnlyEvenArrayByFor = a => { const b = [] let i = 0; for (const n of a) { if (n % 2 == 0) { b[i++] = n } } return b } /* filter */ const getOnlyEvenArrayByFilter = a => { return a.filter(n => n % 2 == 0) } const getOnlyEvenArrayByFilterOneLiner = a => a.filter(n => n % 2 == 0) p(getOnlyEvenArrayByFor(a)) p(getOnlyEvenArrayByFilter(a)) p(getOnlyEvenArrayByFilterOneLiner(a)) |
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[ -2, -1, 0, 1, 2, 3, 4, 5 ] [ -2, 0, 2, 4 ] [ -2, 0, 2, 4 ] [ -2, 0, 2, 4 ] |
JavaScriptのPromise配列とPromise.all()の練習
JavaScriptのPromise配列とPromise.all()の練習
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const main = () => { const p = console.log const getTimeoutPromise = (func, arg, time_ms) => { return new Promise((resolve, reject) => { setTimeout(() => { func(arg) resolve(arg) }, time_ms) }) } const execPromises_getTimeLapse = (promises, funcForResults) => { const startTime_ms = new Date() Promise.all(promises).then(results => { funcForResults(results) const endTime_ms = new Date() const timelapse_ms = endTime_ms - startTime_ms p("timelapse_ms : " + timelapse_ms) }); } const sub = () => { const promises = [] promises.push(getTimeoutPromise(p, "timeout1", 7)) promises.push(getTimeoutPromise(p, "timeout2", 0)) promises.push(getTimeoutPromise(p, "timeout3", 54)) promises.push(getTimeoutPromise(p, "timeout4", 32)) promises.push(getTimeoutPromise(p, "timeout5", 2)) execPromises_getTimeLapse(promises, p) } sub() } main() |
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timeout2 timeout5 timeout1 timeout4 timeout3 [ 'timeout1', 'timeout2', 'timeout3', 'timeout4', 'timeout5' ] timelapse_ms : 56 |
JavaScriptのオブジェクトの比較は不思議である
JavaScriptのオブジェクトの比較は不思議である
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const p = console.log p("{} == {} : " + ( {} == {} ) ) p("{} === {} : " + ( {} === {} ) ) p("{} < {} : " + ( {} < {} ) ) p("{} > {} : " + ( {} > {} ) ) p("{} <= {} : " + ( {} <= {} ) ) p("{} >= {} : " + ( {} >= {} ) ) |
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{} == {} : false {} === {} : false {} < {} : false {} > {} : false {} <= {} : true {} >= {} : true |
リアルタイムチャット(ajax)
リアルタイムチャット(ajax)
最大公約数を求める
最大公約数を求める
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const main = () => { 'use strict' const p = console.log const calcGreatestCommonFactor = (arg1, arg2) => { let a = Number(arg1) let b = Number(arg2) /* 絶対値にする */ if (a < 0) { a *= -1 } if (b < 0) { b *= -1 } /* 同じ値ならそのまま返却する */ if (a === b) { return a } /* 片方が0ならもう片方の値が最大公約数になる */ if (a === 0) { return b } if (b === 0) { return a } /* aの方を大きくする */ if (a < b) { const c = a a = b b = c } // 余り(初期値は引数の小さい方) let rem = b /* 最大公約数を求めるループ */ while (true) { rem = a % b /* 割り切れたら、その時割った値が最大公約数 */ if (rem === 0) { return b } a = b b = rem } } const spacePadding = (n, keta = 4) => { const strN = '' + n const nKeta = strN.length if (keta < nKeta) { return strN } let pad = '' for (let i = 0; i < keta; i++) { pad += ' ' } return (pad + strN).slice(-keta) } const dispGreatestCommonFactor = (a, b) => { let gcf = calcGreatestCommonFactor(a, b) a = spacePadding(a) b = spacePadding(b) gcf = spacePadding(gcf) p(`${a} と ${b} の最大公約数は ${gcf}`) } /* 最大公約数を求めて出力する */ dispGreatestCommonFactor(4997, 7890); dispGreatestCommonFactor(147, 105); dispGreatestCommonFactor(0, 19); } main() |
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4997 と 7890 の最大公約数は 263 147 と 105 の最大公約数は 21 0 と 19 の最大公約数は 19 |
