JavaScript

2018.08.22

その年最初の落雷が起こった日の統計

1年間に平均12回雷が落ちる街がある。
1日あたりの落雷の発生確率を3.29%とすると、
その年最初の落雷が起こった日となる確率は、1月1日から数えて何日がいちばん高いか。

こたえ：1月1日

const p = console.log;
const probabilityOf = (percent) => {
  percent = Number(percent);
  if (Math.random() * 100 < percent) {
    return true;
  }
  return false;
};
const calcFirstDay = (percent) => {
  percent = Number(percent);
  if (percent <= 0) {
    p("invalid percent : " + percent);
    return -1;
  }
  let cnt = 0;
  while (true) {
    cnt++;
    if (probabilityOf(percent)) {
      return cnt;
    }
  }
};
const calcCntOfYear = (percent) => {
  let cnt = 0;
  for (let i = 0; i < 365; i++) {
    if (probabilityOf(percent)) {
      cnt++;
    }
  }
  return cnt;
};
const calcAverage = (a) => {
  let sum = 0;
  for (const n of a) {
    sum += n;
  }
  return sum / a.length;
};
const zeroPadding = (NUM, LEN) => {
  return (Array(LEN).join('0') + NUM).slice(-LEN);
};
const spacePadding = (NUM, LEN) => {
  return (Array(LEN).join(' ') + NUM).slice(-LEN);
};
const dispLine = (k, v, per = 1) => {
  let l = "";
  v = v * 1.0 / per;
  for (let i = 0; i < v; i++) {
    l += ".";
  }
  k = spacePadding(k, 3);
  p(k + " : " + l);
};
const dispChart = (a, per = 1) => {
  for (const k of Object.keys(a)) {
    const v = a[k];
    dispLine(k, v, per);
  }
};
const scoreFirstDay = [];
const percent = 3.29;
const times = 100000;
for (let i = 0; i < times; i++) {
  const fd = calcFirstDay(percent);
  if (scoreFirstDay[fd] === undefined) {
    scoreFirstDay[fd] = 1;
  } else {
    scoreFirstDay[fd] += 1;
  }
}

p("その年最初の落雷が起こった日の統計");
p();
p("1日あたりの落雷が起こる確率 : " + percent + "%");
p("観測年数 : " + times + "年");
p();
p("[日/年数(30分の1)]");

dispChart(scoreFirstDay, 30);

const p = console.log;

const probabilityOf = (percent) => {

percent = Number(percent);

if (Math.random() * 100 < percent) {

return true;

}

return false;

};

const calcFirstDay = (percent) => {

percent = Number(percent);

if (percent <= 0) {

p("invalid percent : " + percent);

return -1;

}

let cnt = 0;

while (true) {

cnt++;

if (probabilityOf(percent)) {

return cnt;

}

};

const calcCntOfYear = (percent) => {

let cnt = 0;

for (let i = 0; i < 365; i++) {

if (probabilityOf(percent)) {

cnt++;

}

return cnt;

};

const calcAverage = (a) => {

let sum = 0;

for (const n of a) {

sum += n;

}

return sum / a.length;

};

const zeroPadding = (NUM, LEN) => {

return (Array(LEN).join('0') + NUM).slice(-LEN);

};

const spacePadding = (NUM, LEN) => {

return (Array(LEN).join(' ') + NUM).slice(-LEN);

};

const dispLine = (k, v, per = 1) => {

let l = "";

v = v * 1.0 / per;

for (let i = 0; i < v; i++) {

l += ".";

}

k = spacePadding(k, 3);

p(k + " : " + l);

};

const dispChart = (a, per = 1) => {

for (const k of Object.keys(a)) {

const v = a[k];

dispLine(k, v, per);

}

};

const scoreFirstDay = [];

const percent = 3.29;

const times = 100000;

for (let i = 0; i < times; i++) {

const fd = calcFirstDay(percent);

if (scoreFirstDay[fd] === undefined) {

scoreFirstDay[fd] = 1;

} else {

scoreFirstDay[fd] += 1;

}

p("その年最初の落雷が起こった日の統計");

p();

p("1日あたりの落雷が起こる確率 : " + percent + "%");

p("観測年数 : " + times + "年");

p();

p("[日/年数(30分の1)]");

dispChart(scoreFirstDay, 30);

その年最初の落雷が起こった日の統計

1日あたりの落雷が起こる確率 : 3.29%
観測年数 : 100000年

[日/年数(30分の1)]
  1 : .............................................................................................................
  2 : ............................................................................................................
  3 : ........................................................................................................
  4 : .......................................................................................................
  5 : ...............................................................................................
  6 : .............................................................................................
  7 : ...........................................................................................
  8 : ........................................................................................
  9 : ....................................................................................
 10 : ...................................................................................
 11 : ................................................................................
 12 : ............................................................................
 13 : .........................................................................
 14 : ...................................................................
 15 : ...................................................................
 16 : .................................................................
 17 : .................................................................
 18 : ...............................................................
 19 : .............................................................
 20 : ..........................................................
 21 : .........................................................
 22 : .......................................................
 23 : .......................................................
 24 : ...................................................
 25 : ................................................
 26 : ..............................................
 27 : ...............................................
 28 : ............................................
 29 : .............................................
 30 : ...........................................
 31 : .........................................
 32 : ......................................
 33 : .......................................
 34 : ......................................
 35 : ......................................
 36 : ...................................
 37 : .................................
 38 : ................................
 39 : ..............................
 40 : ...............................
 41 : ...............................
 42 : ..........................
 43 : ...........................
 44 : ...........................
 45 : ..........................
 46 : ...........................
 47 : ......................
 48 : .......................
 49 : .......................
 50 : ......................
 51 : .....................
 52 : ......................
 53 : .....................
 54 : ...................
 55 : ..................
 56 : ..................
 57 : .................
 58 : ................
 59 : ................
 60 : ...............
 61 : ...............
 62 : ...............
 63 : ..............
 64 : ..............
 65 : .............
 66 : .............
 67 : .............
 68 : ............
 69 : ............
 70 : ............
 71 : ..........
 72 : ..........
 73 : ..........
 74 : ..........
 75 : ..........
 76 : .........
 77 : ..........
 78 : .........
 79 : ........
 80 : ........
 81 : .......
 82 : .......
 83 : .......
 84 : ........
 85 : .......
 86 : ......
 87 : ......
 88 : .......
 89 : .......
 90 : .......
 91 : ......
 92 : .....
 93 : ......
 94 : ......
 95 : .....
 96 : ......
 97 : .....
 98 : ....
 99 : .....
100 : ....
101 : ....
102 : .....
103 : ....
104 : ....
105 : ....
106 : ....
107 : ...
108 : ....
109 : ...
110 : ....
111 : ...
112 : ...
113 : ...
114 : ...
115 : ...
116 : ...
117 : ...
118 : ...
119 : ...
120 : ...
121 : ...
122 : ..
123 : ..
124 : ..
125 : ..
126 : ..
127 : ..
128 : ..
129 : ..
130 : ..
131 : ..
132 : ..
133 : .
134 : ..
135 : ..
136 : ..
137 : ..
138 : ..
139 : .
140 : ..
141 : .
142 : .
143 : ..
144 : .
145 : .
146 : .
147 : ..
148 : .
149 : .
150 : .
151 : .
152 : .
153 : .
154 : .
155 : .
156 : .
157 : .
158 : .
159 : .
160 : .
161 : .
162 : .
163 : .
164 : .
165 : .
166 : .
167 : .
168 : .
169 : .
170 : .
171 : .
172 : .
173 : .
174 : .
175 : .
176 : .
177 : .
178 : .
179 : .
180 : .
181 : .
182 : .
183 : .
184 : .
185 : .
186 : .
187 : .
188 : .
189 : .
190 : .
191 : .
192 : .
193 : .
194 : .
195 : .
196 : .
197 : .
198 : .
199 : .
200 : .
201 : .
202 : .
203 : .
204 : .
205 : .
206 : .
207 : .
208 : .
209 : .
210 : .
212 : .
213 : .
214 : .
216 : .
217 : .
218 : .
219 : .
220 : .
221 : .
223 : .
224 : .
226 : .
227 : .
229 : .
230 : .
231 : .
232 : .
234 : .
235 : .
237 : .
238 : .
239 : .
240 : .
241 : .
242 : .
243 : .
244 : .
245 : .
248 : .
249 : .
251 : .
252 : .
253 : .
255 : .
256 : .
257 : .
258 : .
262 : .
265 : .
271 : .
277 : .
279 : .
280 : .
291 : .
294 : .
300 : .
305 : .
413 : .

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

138

139

140

141

142

143

144

145

146

147

148

149

150

151

152

153

154

155

156

157

158

159

160

161

162

163

164

165

166

167

168

169

170

171

172

173

174

175

176

177

178

179

180

181

182

183

184

185

186

187

188

189

190

191

192

193

194

195

196

197

198

199

200

201

202

203

204

205

206

207

208

209

210

211

212

213

214

215

216

217

218

219

220

221

222

223

224

225

226

227

228

229

230

231

232

233

234

235

236

237

238

239

240

241

242

243

244

245

246

247

248

249

250

251

252

253

254

255

256

257

258

259

260

261

262

263

264

その年最初の落雷が起こった日の統計

1日あたりの落雷が起こる確率 : 3.29%

観測年数 : 100000年

[日/年数(30分の1)]

1 : .............................................................................................................

2 : ............................................................................................................

3 : ........................................................................................................

4 : .......................................................................................................

5 : ...............................................................................................

6 : .............................................................................................

7 : ...........................................................................................

8 : ........................................................................................

9 : ....................................................................................

10 : ...................................................................................

11 : ................................................................................

12 : ............................................................................

13 : .........................................................................

14 : ...................................................................

15 : ...................................................................

16 : .................................................................

17 : .................................................................

18 : ...............................................................

19 : .............................................................

20 : ..........................................................

21 : .........................................................

22 : .......................................................

23 : .......................................................

24 : ...................................................

25 : ................................................

26 : ..............................................

27 : ...............................................

28 : ............................................

29 : .............................................

30 : ...........................................

31 : .........................................

32 : ......................................

33 : .......................................

34 : ......................................

35 : ......................................

36 : ...................................

37 : .................................

38 : ................................

39 : ..............................

40 : ...............................

41 : ...............................

42 : ..........................

43 : ...........................

44 : ...........................

45 : ..........................

46 : ...........................

47 : ......................

48 : .......................

49 : .......................

50 : ......................

51 : .....................

52 : ......................

53 : .....................

54 : ...................

55 : ..................

56 : ..................

57 : .................

58 : ................

59 : ................

60 : ...............

61 : ...............

62 : ...............

63 : ..............

64 : ..............

65 : .............

66 : .............

67 : .............

68 : ............

69 : ............

70 : ............

71 : ..........

72 : ..........

73 : ..........

74 : ..........

75 : ..........

76 : .........

77 : ..........

78 : .........

79 : ........

80 : ........

81 : .......

82 : .......

83 : .......

84 : ........

85 : .......

86 : ......

87 : ......

88 : .......

89 : .......

90 : .......

91 : ......

92 : .....

93 : ......

94 : ......

95 : .....

96 : ......

97 : .....

98 : ....

99 : .....

100 : ....

101 : ....

102 : .....

103 : ....

104 : ....

105 : ....

106 : ....

107 : ...

108 : ....

109 : ...

110 : ....

111 : ...

112 : ...

113 : ...

114 : ...

115 : ...

116 : ...

117 : ...

118 : ...

119 : ...

120 : ...

121 : ...

122 : ..

123 : ..

124 : ..

125 : ..

126 : ..

127 : ..

128 : ..

129 : ..

130 : ..

131 : ..

132 : ..

133 : .

134 : ..

135 : ..

136 : ..

137 : ..

138 : ..

139 : .

140 : ..

141 : .

142 : .

143 : ..

144 : .

145 : .

146 : .

147 : ..

148 : .

149 : .

150 : .

151 : .

152 : .

153 : .

154 : .

155 : .

156 : .

157 : .

158 : .

159 : .

160 : .

161 : .

162 : .

163 : .

164 : .

165 : .

166 : .

167 : .

168 : .

169 : .

170 : .

171 : .

172 : .

173 : .

174 : .

175 : .

176 : .

177 : .

178 : .

179 : .

180 : .

181 : .

182 : .

183 : .

184 : .

185 : .

186 : .

187 : .

188 : .

189 : .

190 : .

191 : .

192 : .

193 : .

194 : .

195 : .

196 : .

197 : .

198 : .

199 : .

200 : .

201 : .

202 : .

203 : .

204 : .

205 : .

206 : .

207 : .

208 : .

209 : .

210 : .

212 : .

213 : .

214 : .

216 : .

217 : .

218 : .

219 : .

220 : .

221 : .

223 : .

224 : .

226 : .

227 : .

229 : .

230 : .

231 : .

232 : .

234 : .

235 : .

237 : .

238 : .

239 : .

240 : .

241 : .

242 : .

243 : .

244 : .

245 : .

248 : .

249 : .

251 : .

252 : .

253 : .

255 : .

256 : .

257 : .

258 : .

262 : .

265 : .

271 : .

277 : .

279 : .

280 : .

291 : .

294 : .

300 : .

305 : .

413 : .

2018.08.19

ループとコールバックの問題(一応解決)

関数を外部で宣言しておくと期待通り動くらしい。

var ps = [];
var len = 5;

const metafunc = (func, arg) => {
    func(arg);
};

for(var i=0; i<len; i++){
    ps.push(new Promise(resolve => {
        setTimeout(
            metafunc(resolve, i),
            0
        );
    }));    
}
Promise.all(ps).then(results => {
    console.log(results)
});

var ps = [];

var len = 5;

const metafunc = (func, arg) => {

func(arg);

};

for(var i=0; i<len; i++){

ps.push(new Promise(resolve => {

setTimeout(

metafunc(resolve, i),

);

}));

}

Promise.all(ps).then(results => {

console.log(results)

});

[ 0, 1, 2, 3, 4 ]

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

2018.08.18

ループとコールバックの問題(未解決)

これ謎すぎる

var ps = [];
var len = 5;
for(var i=0; i<len; i++){
    ps.push(new Promise(resolve => {
        setTimeout(()=>{
            resolve(i);
        }, 0);
    }));    
}
Promise.all(ps).then(results => {
    console.log(results)
});

var ps = [];

var len = 5;

for(var i=0; i<len; i++){

ps.push(new Promise(resolve => {

setTimeout(()=>{

resolve(i);

}, 0);

}));

}

Promise.all(ps).then(results => {

console.log(results)

});

[ 5, 5, 5, 5, 5 ]

1	[ 5, 5, 5, 5, 5 ]

2018.08.08

keyを保持したままvalueでソート

javascriptはkeyが勝手に昇順ソートされる。
そういうことはしないで欲しい。

// (u.js)
'use strict';
module.exports = {
  p(a) {
    if(undefined === a){
      a = '';
    }
    console.log(a);
  },
  foreach(obj, func) {
    for (const key of Object.keys(obj)) {
      const value = obj[key];
      func(key, value);
    }
  },
  dispKeyValue(k, v) {
    console.log(k + " => " + v);
  },
  getRandomInt(min = 0, max = 9) {
    min = Number(min);
    max = Number(max);
    if (max <= min) {
      return max;
    }
    const randomOffset = Math.floor(Math.random() * (max - min + 1));
    return min + randomOffset;
  }
};

// (u.js)

'use strict';

module.exports = {

p(a) {

if(undefined === a){

a = '';

}

console.log(a);

foreach(obj, func) {

for (const key of Object.keys(obj)) {

const value = obj[key];

func(key, value);

}

dispKeyValue(k, v) {

console.log(k + " => " + v);

getRandomInt(min = 0, max = 9) {

min = Number(min);

max = Number(max);

if (max <= min) {

return max;

}

const randomOffset = Math.floor(Math.random() * (max - min + 1));

return min + randomOffset;

}

};

// (Main.js)
main();

function main() {
  'use strict';
  const u = require('./u');
  const swap = (a, l, r) => {
    const t = a[l];
    a[l] = a[r];
    a[r] = t;
  };
  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 getKeyOfValue = (a, v) => {
    for (const key of Object.keys(a)) {
      const value = a[key];
      if (v === value) {
        return key;
      }
    }
    return null;
  };
  const getDeepCopy = (a) => {
    let b = [];
    for(const k of Object.keys(a)){
        const v = a[k];
        b[k] = v;
    }
    return b;
  };
  const deepCopy_fromAtoB = (a, b) => {
      u.foreach(b, (k, v) => {
        delete b[k];
      });
      
      u.foreach(a, (k, v) => {
          b[k] = v;
      });
  };
  const bubblesort_keepkey = (a) => {
    let b = getDeepCopy(a);
    bubblesort(b);
    let c = [];
    for (const v of b) {
      const key = getKeyOfValue(a, v);
      c['_' + key] = v;
    }
//    a = getDeepCopy(c);
    deepCopy_fromAtoB(c, a);
  };
  const sub = () => {
    const times = 1000000;
    const a = [];
    for (let i = 0; i < times; i++) {
      const n = u.getRandomInt(0, 10);
      if (undefined === a[n]) {
        a[n] = 1;
      } else {
        a[n] += 1;
      }
    }
    bubblesort_keepkey(a);
    u.foreach(a, u.dispKeyValue);
  };
  // 実質、main関数
  sub();
}

// (Main.js)

main();

function main() {

'use strict';

const u = require('./u');

const swap = (a, l, r) => {

const t = a[l];

a[l] = a[r];

a[r] = t;

};

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 getKeyOfValue = (a, v) => {

for (const key of Object.keys(a)) {

const value = a[key];

if (v === value) {

return key;

}

return null;

};

const getDeepCopy = (a) => {

let b = [];

for(const k of Object.keys(a)){

const v = a[k];

b[k] = v;

}

return b;

};

const deepCopy_fromAtoB = (a, b) => {

u.foreach(b, (k, v) => {

delete b[k];

});

u.foreach(a, (k, v) => {

b[k] = v;

});

};

const bubblesort_keepkey = (a) => {

let b = getDeepCopy(a);

bubblesort(b);

let c = [];

for (const v of b) {

const key = getKeyOfValue(a, v);

c['_' + key] = v;

}

// a = getDeepCopy(c);

deepCopy_fromAtoB(c, a);

};

const sub = () => {

const times = 1000000;

const a = [];

for (let i = 0; i < times; i++) {

const n = u.getRandomInt(0, 10);

if (undefined === a[n]) {

a[n] = 1;

} else {

a[n] += 1;

}

bubblesort_keepkey(a);

u.foreach(a, u.dispKeyValue);

};

// 実質、main関数

sub();

}

_8 => 90527
_3 => 90615
_2 => 90618
_9 => 90679
_6 => 90697
_0 => 90701
_5 => 91005
_7 => 91153
_4 => 91288
_1 => 91310
_10 => 91407

_8 => 90527

_3 => 90615

_2 => 90618

_9 => 90679

_6 => 90697

_0 => 90701

_5 => 91005

_7 => 91153

_4 => 91288

_1 => 91310

_10 => 91407

2018.08.08

javascriptのコールバックとbind

// (u.js)
'use strict';
 
module.exports = {
    p(a) {
        console.log(a);
    },
    foreach(obj, func) {
        for (const key of Object.keys(obj)) {
            const value = obj[key];
            func(key, value);
        }
    },
    dispKeyValue(k, v) {
        this.p(k + " => " + v);
    }
};

// (u.js)

'use strict';

module.exports = {

p(a) {

console.log(a);

foreach(obj, func) {

for (const key of Object.keys(obj)) {

const value = obj[key];

func(key, value);

}

dispKeyValue(k, v) {

this.p(k + " => " + v);

}

};

// (main.js)
const u = require('./u');

const taro = {
  phrase: "こんにちは",
  name: "たろう",
  age: 19,
  greeting() {
    p(this.phrase + ", " + this.name + "(" + this.age + ")です。");
  },
};

// u.foreach(taro, u.dispKeyValue); // TypeError: Cannot read property 'p' of undefined
u.foreach(taro, u.dispKeyValue.bind(u));

// (main.js)

const u = require('./u');

const taro = {

phrase: "こんにちは",

name: "たろう",

age: 19,

greeting() {

p(this.phrase + ", " + this.name + "(" + this.age + ")です。");

};

// u.foreach(taro, u.dispKeyValue); // TypeError: Cannot read property 'p' of undefined

u.foreach(taro, u.dispKeyValue.bind(u));

phrase => こんにちは
name => たろう
age => 19
greeting => greeting() {
    p(this.phrase + ", " + this.name + "(" + this.age + ")です。");
  }

phrase => こんにちは

name => たろう

age => 19

greeting => greeting() {

p(this.phrase + ", " + this.name + "(" + this.age + ")です。");

}

2018.08.06

javascript(node.js)のライブラリを作る

練習がてら、安全とされるforeachの関数を作ってみた。
コールバック関数は毎回呼ばれるわけだから、
特定のkeyなりvalueなりを発見したらbreakまたはreturnするということができないので、
値を探すときには使えない。

// u.js
'use strict';

module.exports = {
    p: (a) => {
        console.log(a);
    },
    foreach: (obj, func) => {
        for (const key of Object.keys(obj)) {
            const value = obj[key];
            func(key, value);
        }
    }
}

// u.js

'use strict';

module.exports = {

p: (a) => {

console.log(a);

foreach: (obj, func) => {

for (const key of Object.keys(obj)) {

const value = obj[key];

func(key, value);

}

// main.js
const main = () => {
    'use strict';

    const u = require('./u');
    let taro = {
        phrase: "こんにちは",
        name: "たろう",
        age: 19,
        greeting(){
            p(this.phrase + ", " + this.name + "(" + this.age + ")です。");
        }
    };
    u.foreach(taro, (k, v) => {
        u.p(k + " : " + v);
        if(v === "たろう"){
            u.p("=== たろうを発見 ===");
            return;
        }
    });
}

main();

// main.js

const main = () => {

'use strict';

const u = require('./u');

let taro = {

phrase: "こんにちは",

name: "たろう",

age: 19,

greeting(){

p(this.phrase + ", " + this.name + "(" + this.age + ")です。");

}

};

u.foreach(taro, (k, v) => {

u.p(k + " : " + v);

if(v === "たろう"){

u.p("=== たろうを発見 ===");

return;

}

});

}

main();

$ node main.js
phrase : こんにちは
name : たろう
=== 発見 ===
age : 19
greeting : greeting(){
            p(this.phrase + ", " + this.name + "(" + this.age + ")です。");
        }

$ node main.js

phrase : こんにちは

name : たろう

=== 発見 ===

age : 19

greeting : greeting(){

p(this.phrase + ", " + this.name + "(" + this.age + ")です。");

}

2018.08.03

JavaScriptでカリー化

これ何が便利なのかわからん。

/*
カリー化 (currying, カリー化された=curried) とは、複数の引数をとる関数を、
引数が「もとの関数の最初の引数」で戻り値が
「もとの関数の残りの引数を取り結果を返す関数」
であるような関数にすること（あるいはその関数のこと）である。
*/
main();

function p(a){
    console.log(a);
}
function main(){
    var ret = sub(3, 5);
    p(ret);
    var ret = currySub(3)(5);
    p(ret);
}
function sub(a, b){
    return a - b;
}
function currySub(a){
    return function(b){
        return sub(a, b);
    };
}

カリー化 (currying, カリー化された=curried) とは、複数の引数をとる関数を、

引数が「もとの関数の最初の引数」で戻り値が

「もとの関数の残りの引数を取り結果を返す関数」

であるような関数にすること（あるいはその関数のこと）である。

main();

function p(a){

console.log(a);

}

function main(){

var ret = sub(3, 5);

p(ret);

var ret = currySub(3)(5);

p(ret);

}

function sub(a, b){

return a - b;

}

function currySub(a){

return function(b){

return sub(a, b);

};

}

-2
-2

-2

2018.06.30

オイラーとかゼータ関数とか

const PI = 3.14159265359;

function sum_zeta_2(n){
    var sum = 0;
    for(var i=1; i<=n; i++){
        sum += 1.0 / (i * i);
    }
    return sum;
}

function main(){
    console.log(sum_zeta_2(10000));
    console.log(PI * PI / 6.0);
}

main();

const PI = 3.14159265359;

function sum_zeta_2(n){

var sum = 0;

for(var i=1; i<=n; i++){

sum += 1.0 / (i * i);

}

return sum;

}

function main(){

console.log(sum_zeta_2(10000));

console.log(PI * PI / 6.0);

}

main();

1.6448340718480652
1.6449340668484431

1 2	1.6448340718480652 1.6449340668484431

2018.05.17

JavaScriptで配列の計算とか

プログラミングの練習

function p(a){
    console.log(a);
}
function createCopyArray(a){
    var b = [];
    for(var k in a){
        b[k] = a[k];
    }
    return b;
}
function reverseArray(a){
    var len = a.length;
    var b = createCopyArray(a);
    for(var i=0; i<len; i++){
        a[i] = b[len-1-i];
    }
}
function calcDiff(a, b){
    a = Number(a);
    b = Number(b);
    if(a<b){
        return b-a;
    }else{
        return a-b;
    }
}
function main(){
    var a = [0,1,2,3,4,5,6,7,8];
    var b = createCopyArray(a);
    var c = [];
    var len = a.length;

    reverseArray(b);

    for(var i=0; i<len; i++){
        c[i] = calcDiff(a[i], b[i]);
    }
    
    p(a);
    p(b);
    p(c);
}

main();

function p(a){

console.log(a);

}

function createCopyArray(a){

var b = [];

for(var k in a){

b[k] = a[k];

}

return b;

}

function reverseArray(a){

var len = a.length;

var b = createCopyArray(a);

for(var i=0; i<len; i++){

a[i] = b[len-1-i];

}

function calcDiff(a, b){

a = Number(a);

b = Number(b);

if(a<b){

return b-a;

}else{

return a-b;

}

function main(){

var a = [0,1,2,3,4,5,6,7,8];

var b = createCopyArray(a);

var c = [];

var len = a.length;

reverseArray(b);

for(var i=0; i<len; i++){

c[i] = calcDiff(a[i], b[i]);

}

p(a);

p(b);

p(c);

}

main();

[ 0, 1, 2, 3, 4, 5, 6, 7, 8 ]
[ 8, 7, 6, 5, 4, 3, 2, 1, 0 ]
[ 8, 6, 4, 2, 0, 2, 4, 6, 8 ]

[ 0, 1, 2, 3, 4, 5, 6, 7, 8 ]

[ 8, 7, 6, 5, 4, 3, 2, 1, 0 ]

[ 8, 6, 4, 2, 0, 2, 4, 6, 8 ]

2018.05.14

javascriptでquicksort(プログラミングの練習)

function p(a){
    console.log(a);
}

function swap(a, l, r){
    var t = a[l];
    a[l] = a[r];
    a[r] = t;
}

function getPivot(a, b, c){
    if(b < a){
        if(a < c){
            return a;
        }else{
            return c < b ? c : b;
        }
    }else{
        if(b < c){
            return b;
        }else{
            return c < a ? c : a;
        }
    }
}

function quicksort(a, left, right){
    if(left === undefined){
        left = 0;
    }
    if(right === undefined){
        right = a.length - 1;
    }
    if(right <= left){
        return;
    }
    var l = left;
    var r = right;
    var 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);
}

function getRandomIntMinMax(min, max){
    min = Number(min);
    max = Number(max);
    if(max < min){
        return max;
    }
    return min + Math.floor(Math.random() * (max - min + 1));
}

function getRandomInt(){
    var min = 0;
    var max = 9;
    return getRandomIntMinMax(min, max);
}

function dispArrayList(a){
    for(var k in a){
        var v = a[k];
        p(k + " => " + v);
    }
}

function setValueFromFuncForArray(a, f){
    var len = a.length;
    for(var i=0; i<len; i++){
        a[i] = f();
    }
}

function setRandomForArray(a){
    setValueFromFuncForArray(a, getRandomInt);
}

function resetArray(a){
    setValueFromFuncForArray(a, ()=>{return 0;});
}

function main(){
    var len = 20;
    var a = Array(len);

    setRandomForArray(a);
    p(a);

    quicksort(a);
    p(a);
}

main();

100

101

102

103

104

105

106

function p(a){

console.log(a);

}

function swap(a, l, r){

var t = a[l];

a[l] = a[r];

a[r] = t;

}

function getPivot(a, b, c){

if(b < a){

if(a < c){

return a;

}else{

return c < b ? c : b;

}

}else{

if(b < c){

return b;

}else{

return c < a ? c : a;

}

function quicksort(a, left, right){

if(left === undefined){

left = 0;

}

if(right === undefined){

right = a.length - 1;

}

if(right <= left){

return;

}

var l = left;

var r = right;

var 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);

}

function getRandomIntMinMax(min, max){

min = Number(min);

max = Number(max);

if(max < min){

return max;

}

return min + Math.floor(Math.random() * (max - min + 1));

}

function getRandomInt(){

var min = 0;

var max = 9;

return getRandomIntMinMax(min, max);

}

function dispArrayList(a){

for(var k in a){

var v = a[k];

p(k + " => " + v);

}

function setValueFromFuncForArray(a, f){

var len = a.length;

for(var i=0; i<len; i++){

a[i] = f();

}

function setRandomForArray(a){

setValueFromFuncForArray(a, getRandomInt);

}

function resetArray(a){

setValueFromFuncForArray(a, ()=>{return 0;});

}

function main(){

var len = 20;

var a = Array(len);

setRandomForArray(a);

p(a);

quicksort(a);

p(a);

}

main();

[ 7, 2, 7, 3, 0, 5, 8, 4, 5, 9, 3, 1, 8, 5, 9, 3, 2, 6, 2, 6 ]
[ 0, 1, 2, 2, 2, 3, 3, 3, 4, 5, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9 ]

1 2	[ 7, 2, 7, 3, 0, 5, 8, 4, 5, 9, 3, 1, 8, 5, 9, 3, 2, 6, 2, 6 ] [ 0, 1, 2, 2, 2, 3, 3, 3, 4, 5, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9 ]

5 6 7 8910 11 12

JavaScript

その年最初の落雷が起こった日の統計

ループとコールバックの問題(一応解決)

ループとコールバックの問題(未解決)

keyを保持したままvalueでソート

javascriptのコールバックとbind

javascript(node.js)のライブラリを作る

JavaScriptでカリー化

オイラーとかゼータ関数とか

JavaScriptで配列の計算とか

javascriptでquicksort(プログラミングの練習)

最近の投稿

サイトマップ

カテゴリー

アーカイブ

人気の投稿とページ

Twitter