JavaScript

2020.01.18

twitterで見かけた問題。トビウオ問題

考えれば考えるほどわからなくなってきて、どれも当てはまらないんじゃ、、！？とも思った
結局一番最初に書いたウミガメとタコにしたけど、答案集めたらみんな答え違った😂😂😂 pic.twitter.com/gRPyQddRuo

— K@文系情報学部生(無言フォローすみません) (@beer_nomitaii) January 17, 2020

const トビウオ = {
  は海に住んでいる: true,
  は魚だ: true,
  には足がある: false,
  は鳥だ: false,
};
const クワガタ = {
  は海に住んでいる: false,
  は魚だ: false,
  には足がある: true,
  は鳥だ: false,
};
const コイ = {
  は海に住んでいる: false,
  は魚だ: true,
  には足がある: true,
  は鳥だ: false,
};
const カラス = {
  は海に住んでいる: false,
  は魚だ: false,
  には足がある: true,
  は鳥だ: true,
};
const イルカ = {
  は海に住んでいる: true,
  は魚だ: false,
  には足がある: false,
  は鳥だ: false,
};
const ウミガメ = {
  は海に住んでいる: true,
  は魚だ: false,
  には足がある: true,
  は鳥だ: false,
};
const タコ = {
  は海に住んでいる: true,
  は魚だ: false,
  には足がある: true,
  は鳥だ: false,
};
const ヘビ = {
  は海に住んでいる: false,
  は魚だ: false,
  には足がある: false,
  は鳥だ: false,
};

const f = x => (
  (x.は海に住んでいる ^ !(x.は魚だ)) & (x.には足がある | x.は鳥だ)
);

const xにあてはまるリスト = [];

if (f(トビウオ)) xにあてはまるリスト.push("トビウオ");
if (f(クワガタ)) xにあてはまるリスト.push("クワガタ");
if (f(コイ)) xにあてはまるリスト.push("コイ");
if (f(カラス)) xにあてはまるリスト.push("カラス");
if (f(イルカ)) xにあてはまるリスト.push("イルカ");
if (f(ウミガメ)) xにあてはまるリスト.push("ウミガメ");
if (f(タコ)) xにあてはまるリスト.push("タコ");
if (f(ヘビ)) xにあてはまるリスト.push("ヘビ");

console.log("xにあてはまるリスト : " + xにあてはまるリスト);

const トビウオ = {

は海に住んでいる: true,

は魚だ: true,

には足がある: false,

は鳥だ: false,

};

const クワガタ = {

は海に住んでいる: false,

は魚だ: false,

には足がある: true,

は鳥だ: false,

};

const コイ = {

は海に住んでいる: false,

は魚だ: true,

には足がある: true,

は鳥だ: false,

};

const カラス = {

は海に住んでいる: false,

は魚だ: false,

には足がある: true,

は鳥だ: true,

};

const イルカ = {

は海に住んでいる: true,

は魚だ: false,

には足がある: false,

は鳥だ: false,

};

const ウミガメ = {

は海に住んでいる: true,

は魚だ: false,

には足がある: true,

は鳥だ: false,

};

const タコ = {

は海に住んでいる: true,

は魚だ: false,

には足がある: true,

は鳥だ: false,

};

const ヘビ = {

は海に住んでいる: false,

は魚だ: false,

には足がある: false,

は鳥だ: false,

};

const f = x => (

(x.は海に住んでいる ^ !(x.は魚だ)) & (x.には足がある | x.は鳥だ)

);

const xにあてはまるリスト = [];

if (f(トビウオ)) xにあてはまるリスト.push("トビウオ");

if (f(クワガタ)) xにあてはまるリスト.push("クワガタ");

if (f(コイ)) xにあてはまるリスト.push("コイ");

if (f(カラス)) xにあてはまるリスト.push("カラス");

if (f(イルカ)) xにあてはまるリスト.push("イルカ");

if (f(ウミガメ)) xにあてはまるリスト.push("ウミガメ");

if (f(タコ)) xにあてはまるリスト.push("タコ");

if (f(ヘビ)) xにあてはまるリスト.push("ヘビ");

console.log("xにあてはまるリスト : " + xにあてはまるリスト);

xにあてはまるリスト : クワガタ,カラス

1	xにあてはまるリスト : クワガタ,カラス

2020.01.14

オブジェクト指向オリンピック級タイタニック号のたとえ(JavaScript)

const オリンピック = class {
    constructor(name){
        this.name = name;
    }
    toString() {
        return `この艦はオリンピック級${this.name}号です`;
    }
};

const ships = [];

ships.push(new オリンピック("オリンピック"));
ships.push(new オリンピック("タイタニック"));
ships.push(new オリンピック("ブリタニック"));

ships.forEach(ship => console.log('' + ship));

const オリンピック = class {

constructor(name){

this.name = name;

}

toString() {

return `この艦はオリンピック級${this.name}号です`;

}

};

const ships = [];

ships.push(new オリンピック("オリンピック"));

ships.push(new オリンピック("タイタニック"));

ships.push(new オリンピック("ブリタニック"));

ships.forEach(ship => console.log('' + ship));

この艦はオリンピック級オリンピック号です
この艦はオリンピック級タイタニック号です
この艦はオリンピック級ブリタニック号です

この艦はオリンピック級オリンピック号です

この艦はオリンピック級タイタニック号です

この艦はオリンピック級ブリタニック号です

2019.12.27

node.jsでStreamのpipe

const http = require('http');
const server = http.createServer((req, res) => {
  req.pipe(res);
});
server.listen(3000);

const http = require('http');

const server = http.createServer((req, res) => {

req.pipe(res);

});

server.listen(3000);

// requeset by curl
curl -X POST -H "Content-Type: application/json" -d '{"Name":"sensuikan1973", "Age":"100"}' localhost:3000

1 2	// requeset by curl curl -X POST -H "Content-Type: application/json" -d '{"Name":"sensuikan1973", "Age":"100"}' localhost:3000

// response
{"Name":"sensuikan1973", "Age":"100"}%

1 2	// response {"Name":"sensuikan1973", "Age":"100"}%

2019.10.18

JavaScriptのコールバック関数を引数付きで実行する方法

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。

const p = console.log;

const disp = arg => {
  p(arg);
};

setTimeout(() => {
  const str = 'delay : ' + 13;
  disp(str);
}, 13);

const p = console.log;

const disp = arg => {

p(arg);

};

setTimeout(() => {

const str = 'delay : ' + 13;

disp(str);

}, 13);

delay : 13

1	delay : 13

2019.10.12

求人5社の言語別の求人数の各平均値を求めた

(data.csv)

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

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)

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()

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()

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

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

2019.10.02

クイックソートとバブルソートを両方やる

'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()

100

101

102

103

104

105

106

107

108

'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()

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

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

2019.09.25

JavaScriptでquicksort

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()

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()

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 ]

1 2	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 ]

2019.09.08

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

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)
}

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)

}

2019.08.26

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

'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))

'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))

[ -2, -1, 0, 1, 2, 3, 4, 5 ]
[ -2, 0, 2, 4 ]
[ -2, 0, 2, 4 ]
[ -2, 0, 2, 4 ]

[ -2, -1, 0, 1, 2, 3, 4, 5 ]

[ -2, 0, 2, 4 ]

2019.04.07

JavaScriptのPromise配列とPromise.all()の練習

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()

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()

timeout2
timeout5
timeout1
timeout4
timeout3
[ 'timeout1', 'timeout2', 'timeout3', 'timeout4', 'timeout5' ]
timelapse_ms : 56

timeout2

timeout5

timeout1

timeout4

timeout3

[ 'timeout1', 'timeout2', 'timeout3', 'timeout4', 'timeout5' ]

timelapse_ms : 56

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クイックソートとバブルソートを両方やる

JavaScriptでquicksort

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

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

JavaScriptのPromise配列とPromise.all()の練習

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