210 lines
9.5 KiB
Plaintext
Generated
210 lines
9.5 KiB
Plaintext
Generated
<!DOCTYPE html>
|
||
<html>
|
||
<head>
|
||
<meta charset="utf-8">
|
||
<title>Go в примерах: Ряд (Range)</title>
|
||
<link rel=stylesheet href="site.css">
|
||
</head>
|
||
<script>
|
||
onkeydown = (e) => {
|
||
|
||
if (e.key == "ArrowLeft") {
|
||
window.location.href = 'maps';
|
||
}
|
||
|
||
|
||
if (e.key == "ArrowRight") {
|
||
window.location.href = 'functions';
|
||
}
|
||
|
||
}
|
||
</script>
|
||
<body>
|
||
<div class="example" id="range">
|
||
<h2><a href="./">Go в примерах</a>: Ряд (Range)</h2>
|
||
|
||
<table>
|
||
|
||
<tr>
|
||
<td class="docs">
|
||
<p><em>range</em> перебирает элементы в различных структурах
|
||
данных. Давайте посмотрим, как использовать
|
||
<code>range</code> с некоторыми из структур данных, которые
|
||
мы уже изучили.</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/4GBukIe-7ie" 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="s">"fmt"</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>В данном примере мы используем <code>range</code> для
|
||
подсчета суммы чисел в срезе.
|
||
Для массива синтаксис будет такой же.</p>
|
||
|
||
</td>
|
||
<td class="code leading">
|
||
|
||
<div class="highlight"><pre> <span class="nx">nums</span> <span class="o">:=</span> <span class="p">[]</span><span class="kt">int</span><span class="p">{</span><span class="mi">2</span><span class="p">,</span> <span class="mi">3</span><span class="p">,</span> <span class="mi">4</span><span class="p">}</span>
|
||
<span class="nx">sum</span> <span class="o">:=</span> <span class="mi">0</span>
|
||
<span class="k">for</span> <span class="nx">_</span><span class="p">,</span> <span class="nx">num</span> <span class="o">:=</span> <span class="k">range</span> <span class="nx">nums</span> <span class="p">{</span>
|
||
<span class="nx">sum</span> <span class="o">+=</span> <span class="nx">num</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="s">"sum:"</span><span class="p">,</span> <span class="nx">sum</span><span class="p">)</span>
|
||
</pre></div>
|
||
|
||
</td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td class="docs">
|
||
<p><code>range</code> для массивов и срезов возвращает индекс
|
||
и значение для каждого элемента. Если нам не
|
||
требуется индекс, мы можем использовать оператор
|
||
<code>_</code> для игнорирования. Иногда нам действительно
|
||
необходимы индексы.</p>
|
||
|
||
</td>
|
||
<td class="code leading">
|
||
|
||
<div class="highlight"><pre> <span class="k">for</span> <span class="nx">i</span><span class="p">,</span> <span class="nx">num</span> <span class="o">:=</span> <span class="k">range</span> <span class="nx">nums</span> <span class="p">{</span>
|
||
<span class="k">if</span> <span class="nx">num</span> <span class="o">==</span> <span class="mi">3</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="s">"index:"</span><span class="p">,</span> <span class="nx">i</span><span class="p">)</span>
|
||
<span class="p">}</span>
|
||
<span class="p">}</span>
|
||
</pre></div>
|
||
|
||
</td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td class="docs">
|
||
<p><code>range</code> для карт перебирает пары ключ/значение.</p>
|
||
|
||
</td>
|
||
<td class="code leading">
|
||
|
||
<div class="highlight"><pre> <span class="nx">kvs</span> <span class="o">:=</span> <span class="kd">map</span><span class="p">[</span><span class="kt">string</span><span class="p">]</span><span class="kt">string</span><span class="p">{</span><span class="s">"a"</span><span class="p">:</span> <span class="s">"apple"</span><span class="p">,</span> <span class="s">"b"</span><span class="p">:</span> <span class="s">"banana"</span><span class="p">}</span>
|
||
<span class="k">for</span> <span class="nx">k</span><span class="p">,</span> <span class="nx">v</span> <span class="o">:=</span> <span class="k">range</span> <span class="nx">kvs</span> <span class="p">{</span>
|
||
<span class="nx">fmt</span><span class="p">.</span><span class="nx">Printf</span><span class="p">(</span><span class="s">"%s -> %s\n"</span><span class="p">,</span> <span class="nx">k</span><span class="p">,</span> <span class="nx">v</span><span class="p">)</span>
|
||
<span class="p">}</span>
|
||
</pre></div>
|
||
|
||
</td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td class="docs">
|
||
<p><code>range</code> может перебирать только ключи в карте</p>
|
||
|
||
</td>
|
||
<td class="code leading">
|
||
|
||
<div class="highlight"><pre> <span class="k">for</span> <span class="nx">k</span> <span class="o">:=</span> <span class="k">range</span> <span class="nx">kvs</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="s">"key:"</span><span class="p">,</span> <span class="nx">k</span><span class="p">)</span>
|
||
<span class="p">}</span>
|
||
</pre></div>
|
||
|
||
</td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td class="docs">
|
||
<p><code>range</code> для строк перебирает кодовые точки Unicode.
|
||
Первое значение - это начальный байтовый индекс
|
||
руны, а второе - сама руна.</p>
|
||
|
||
</td>
|
||
<td class="code">
|
||
|
||
<div class="highlight"><pre> <span class="k">for</span> <span class="nx">i</span><span class="p">,</span> <span class="nx">c</span> <span class="o">:=</span> <span class="k">range</span> <span class="s">"go"</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">i</span><span class="p">,</span> <span class="nx">c</span><span class="p">)</span>
|
||
<span class="p">}</span>
|
||
<span class="p">}</span>
|
||
</pre></div>
|
||
|
||
</td>
|
||
</tr>
|
||
|
||
</table>
|
||
|
||
<table>
|
||
|
||
<tr>
|
||
<td class="docs">
|
||
|
||
</td>
|
||
<td class="code">
|
||
|
||
<div class="highlight"><pre><span class="gp">$</span> go run range.go
|
||
<span class="go">sum: 9</span>
|
||
<span class="go">index: 1</span>
|
||
<span class="go">a -> apple</span>
|
||
<span class="go">b -> banana</span>
|
||
<span class="go">key: a</span>
|
||
<span class="go">key: b</span>
|
||
<span class="go">0 103</span>
|
||
<span class="go">1 111</span>
|
||
</pre></div>
|
||
|
||
</td>
|
||
</tr>
|
||
|
||
</table>
|
||
|
||
|
||
<p class="next">
|
||
Следующий пример: <a href="functions">Функции (Functions)</a>.
|
||
</p>
|
||
|
||
<p class="footer">
|
||
by <a href="https://markmcgranaghan.com">Mark McGranaghan</a> | <a href="https://github.com/mmcgrana/gobyexample/blob/master/examples/range">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 \"fmt\"\u000A');codeLines.push('func main() {\u000A');codeLines.push(' nums := []int{2, 3, 4}\u000A sum := 0\u000A for _, num := range nums {\u000A sum += num\u000A }\u000A fmt.Println(\"sum:\", sum)\u000A');codeLines.push(' for i, num := range nums {\u000A if num == 3 {\u000A fmt.Println(\"index:\", i)\u000A }\u000A }\u000A');codeLines.push(' kvs := map[string]string{\"a\": \"apple\", \"b\": \"banana\"}\u000A for k, v := range kvs {\u000A fmt.Printf(\"%s -\x3E %s\\n\", k, v)\u000A }\u000A');codeLines.push(' for k := range kvs {\u000A fmt.Println(\"key:\", k)\u000A }\u000A');codeLines.push(' for i, c := range \"go\" {\u000A fmt.Println(i, c)\u000A }\u000A}\u000A');codeLines.push('');
|
||
</script>
|
||
<script src="site.js" async></script>
|
||
</body>
|
||
</html>
|