yeray/gobyexample
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity
gobyexample/public/random-numbers
badkaktus 7d33b530ed fix links
2019-10-14 23:20:44 +03:00

240 lines
13 KiB
Plaintext
Generated
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Go в примерах: Случайные числа (Random Numbers)</title>
<link rel=stylesheet href="site.css">
</head>
<script>
onkeydown = (e) => {
if (e.key == "ArrowLeft") {
window.location.href = 'time-formatting-parsing';
}
if (e.key == "ArrowRight") {
window.location.href = 'number-parsing';
}
}
</script>
<body>
<div class="example" id="random-numbers">
<h2><a href="./">Go в примерах</a>: Случайные числа (Random Numbers)</h2>
<table>
<tr>
<td class="docs">
<p>Пакет Go <code>math/rand</code> обеспечивает генерацию
<a href="http://en.wikipedia.org/wiki/Pseudorandom_number_generator">псевдослучайных чисел</a>.</p>
</td>
<td class="code empty leading">
</td>
</tr>
<tr>
<td class="docs">
</td>
<td class="code leading">
<a href="http://play.golang.org/p/CKeOTktHnJe" target="_blank"><img title="Run code" src="play.png" class="run" /></a><img title="Copy code" src="clipboard.png" class="copy" />
<div class="highlight"><pre><span class="kn">package</span> <span class="nx">main</span>
</pre></div>
</td>
</tr>
<tr>
<td class="docs">
</td>
<td class="code leading">
<div class="highlight"><pre><span class="kn">import</span> <span class="p">(</span>
<span class="s">&quot;fmt&quot;</span>
<span class="s">&quot;math/rand&quot;</span>
<span class="s">&quot;time&quot;</span>
<span class="p">)</span>
</pre></div>
</td>
</tr>
<tr>
<td class="docs">
</td>
<td class="code leading">
<div class="highlight"><pre><span class="kd">func</span> <span class="nx">main</span><span class="p">()</span> <span class="p">{</span>
</pre></div>
</td>
</tr>
<tr>
<td class="docs">
<p>Например, <code>rand.Intn</code> вернет случайное <code>целое число</code> в
диапазоне <code>0 &lt;= n &lt; 100</code>.</p>
</td>
<td class="code leading">
<div class="highlight"><pre> <span class="nx">fmt</span><span class="p">.</span><span class="nx">Print</span><span class="p">(</span><span class="nx">rand</span><span class="p">.</span><span class="nx">Intn</span><span class="p">(</span><span class="mi">100</span><span class="p">),</span> <span class="s">&quot;,&quot;</span><span class="p">)</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nx">Print</span><span class="p">(</span><span class="nx">rand</span><span class="p">.</span><span class="nx">Intn</span><span class="p">(</span><span class="mi">100</span><span class="p">))</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span><span class="p">()</span>
</pre></div>
</td>
</tr>
<tr>
<td class="docs">
<p><code>rand.Float64</code> вернет <code>число с плавающей точкой</code> в присвоит
его в <code>f</code>, где <code>f</code> будет в промежутке <code>0.0 &lt;= f &lt; 1.0</code>.</p>
</td>
<td class="code leading">
<div class="highlight"><pre> <span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span><span class="p">(</span><span class="nx">rand</span><span class="p">.</span><span class="nx">Float64</span><span class="p">())</span>
</pre></div>
</td>
</tr>
<tr>
<td class="docs">
<p>Этот способ может быть использован для генерации других
случайных чисел с плавающей точкой в разных диапазонах,
например для диапазона <code>5.0 &lt;= f' &lt; 10.0</code>.</p>
</td>
<td class="code leading">
<div class="highlight"><pre> <span class="nx">fmt</span><span class="p">.</span><span class="nx">Print</span><span class="p">((</span><span class="nx">rand</span><span class="p">.</span><span class="nx">Float64</span><span class="p">()</span><span class="o">*</span><span class="mi">5</span><span class="p">)</span><span class="o">+</span><span class="mi">5</span><span class="p">,</span> <span class="s">&quot;,&quot;</span><span class="p">)</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nx">Print</span><span class="p">((</span><span class="nx">rand</span><span class="p">.</span><span class="nx">Float64</span><span class="p">()</span> <span class="o">*</span> <span class="mi">5</span><span class="p">)</span> <span class="o">+</span> <span class="mi">5</span><span class="p">)</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span><span class="p">()</span>
</pre></div>
</td>
</tr>
<tr>
<td class="docs">
<p>Генератор чисел по умолчанию является детерминированным,
поэтому по умолчанию он будет каждый раз генерировать
одну и ту же последовательность чисел. Чтобы произвести
различные последовательности, дайте ему <code>соль</code>(<a href="https://ru.wikipedia.org/wiki/Соль_(криптография)">https://ru.wikipedia.org/wiki/Соль_(криптография)</a>),
которая изменяется. Обратите внимание, что это не
безопасно использовать для генерации случайных чисел,
которые вы намерены хранить в секрете, используйте
<code>crypto/rand</code> для них.</p>
</td>
<td class="code leading">
<div class="highlight"><pre> <span class="nx">s1</span> <span class="o">:=</span> <span class="nx">rand</span><span class="p">.</span><span class="nx">NewSource</span><span class="p">(</span><span class="nx">time</span><span class="p">.</span><span class="nx">Now</span><span class="p">().</span><span class="nx">UnixNano</span><span class="p">())</span>
<span class="nx">r1</span> <span class="o">:=</span> <span class="nx">rand</span><span class="p">.</span><span class="nx">New</span><span class="p">(</span><span class="nx">s1</span><span class="p">)</span>
</pre></div>
</td>
</tr>
<tr>
<td class="docs">
<p>Вызвать результат <code>rand.Rand</code> можно точно так же, как и
функции в пакете <code>rand</code>.</p>
</td>
<td class="code leading">
<div class="highlight"><pre> <span class="nx">fmt</span><span class="p">.</span><span class="nx">Print</span><span class="p">(</span><span class="nx">r1</span><span class="p">.</span><span class="nx">Intn</span><span class="p">(</span><span class="mi">100</span><span class="p">),</span> <span class="s">&quot;,&quot;</span><span class="p">)</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nx">Print</span><span class="p">(</span><span class="nx">r1</span><span class="p">.</span><span class="nx">Intn</span><span class="p">(</span><span class="mi">100</span><span class="p">))</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span><span class="p">()</span>
</pre></div>
</td>
</tr>
<tr>
<td class="docs">
<p>Если вы используете одну и ту же соль для генерации
чисел, то они будут совпадать.</p>
</td>
<td class="code">
<div class="highlight"><pre> <span class="nx">s2</span> <span class="o">:=</span> <span class="nx">rand</span><span class="p">.</span><span class="nx">NewSource</span><span class="p">(</span><span class="mi">42</span><span class="p">)</span>
<span class="nx">r2</span> <span class="o">:=</span> <span class="nx">rand</span><span class="p">.</span><span class="nx">New</span><span class="p">(</span><span class="nx">s2</span><span class="p">)</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nx">Print</span><span class="p">(</span><span class="nx">r2</span><span class="p">.</span><span class="nx">Intn</span><span class="p">(</span><span class="mi">100</span><span class="p">),</span> <span class="s">&quot;,&quot;</span><span class="p">)</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nx">Print</span><span class="p">(</span><span class="nx">r2</span><span class="p">.</span><span class="nx">Intn</span><span class="p">(</span><span class="mi">100</span><span class="p">))</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span><span class="p">()</span>
<span class="nx">s3</span> <span class="o">:=</span> <span class="nx">rand</span><span class="p">.</span><span class="nx">NewSource</span><span class="p">(</span><span class="mi">42</span><span class="p">)</span>
<span class="nx">r3</span> <span class="o">:=</span> <span class="nx">rand</span><span class="p">.</span><span class="nx">New</span><span class="p">(</span><span class="nx">s3</span><span class="p">)</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nx">Print</span><span class="p">(</span><span class="nx">r3</span><span class="p">.</span><span class="nx">Intn</span><span class="p">(</span><span class="mi">100</span><span class="p">),</span> <span class="s">&quot;,&quot;</span><span class="p">)</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nx">Print</span><span class="p">(</span><span class="nx">r3</span><span class="p">.</span><span class="nx">Intn</span><span class="p">(</span><span class="mi">100</span><span class="p">))</span>
<span class="p">}</span>
</pre></div>
</td>
</tr>
</table>
<table>
<tr>
<td class="docs">
</td>
<td class="code leading">
<div class="highlight"><pre><span class="gp">$</span> go run random-numbers.go
<span class="go">81,87</span>
<span class="go">0.6645600532184904</span>
<span class="go">7.123187485356329,8.434115364335547</span>
<span class="go">0,28</span>
<span class="go">5,87</span>
<span class="go">5,87</span>
</pre></div>
</td>
</tr>
<tr>
<td class="docs">
<p>Обратитесь к документации по пакету <a href="http://golang.org/pkg/math/rand/"><code>math/rand</code></a>
для ознакомления с другими случайными величинами,
которые может предоставить Go.</p>
</td>
<td class="code empty">
</td>
</tr>
</table>
<p class="next">
Следующий пример: <a href="number-parsing">Парсинг чисел (Number Parsing)</a>.
</p>
<p class="footer">
by <a href="https://markmcgranaghan.com">Mark McGranaghan</a> | <a href="https://github.com/mmcgrana/gobyexample/blob/master/examples/random-numbers">source</a> | <a href="https://github.com/mmcgrana/gobyexample#license">license</a>
</p>
</div>
<script>
var codeLines = [];
codeLines.push('');codeLines.push('package main\u000A');codeLines.push('import (\u000A \"fmt\"\u000A \"math/rand\"\u000A \"time\"\u000A)\u000A');codeLines.push('func main() {\u000A');codeLines.push(' fmt.Print(rand.Intn(100), \",\")\u000A fmt.Print(rand.Intn(100))\u000A fmt.Println()\u000A');codeLines.push(' fmt.Println(rand.Float64())\u000A');codeLines.push(' fmt.Print((rand.Float64()*5)+5, \",\")\u000A fmt.Print((rand.Float64() * 5) + 5)\u000A fmt.Println()\u000A');codeLines.push(' s1 := rand.NewSource(time.Now().UnixNano())\u000A r1 := rand.New(s1)\u000A');codeLines.push(' fmt.Print(r1.Intn(100), \",\")\u000A fmt.Print(r1.Intn(100))\u000A fmt.Println()\u000A');codeLines.push(' s2 := rand.NewSource(42)\u000A r2 := rand.New(s2)\u000A fmt.Print(r2.Intn(100), \",\")\u000A fmt.Print(r2.Intn(100))\u000A fmt.Println()\u000A s3 := rand.NewSource(42)\u000A r3 := rand.New(s3)\u000A fmt.Print(r3.Intn(100), \",\")\u000A fmt.Print(r3.Intn(100))\u000A}\u000A');codeLines.push('');codeLines.push('');
</script>
<script src="site.js" async></script>
</body>
</html>
Reference in New Issue View Git Blame Copy Permalink