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range-over-channels
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<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Go by Example: Range over Channels</title>
<link rel=stylesheet href="site.css">
</head>
<script>
onkeydown = (e) => {
if (e.key == "ArrowLeft") {
window.location.href = 'closing-channels';
}
if (e.key == "ArrowRight") {
window.location.href = 'timers';
}
}
</script>
<body>
<div class="example" id="range-over-channels">
<h2><a href="./">Go by Example</a>: Range over Channels</h2>
<table>
<tr>
<td class="docs">
<p>In a <a href="range">previous</a> example we saw how <code>for</code> and
<code>range</code> provide iteration over basic data structures.
We can also use this syntax to iterate over
values received from a channel.</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/yQMclmwOYs9"><img title="Run code" src="play.png" class="run" /></a><img title="Copy code" src="clipboard.png" class="copy" />
<pre class="chroma"><span class="kn">package</span> <span class="nx">main</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
</td>
<td class="code leading">
<pre class="chroma"><span class="kn">import</span> <span class="s">"fmt"</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
</td>
<td class="code leading">
<pre class="chroma"><span class="kd">func</span> <span class="nf">main</span><span class="p">()</span> <span class="p">{</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
<p>We’ll iterate over 2 values in the <code>queue</code> channel.</p>
</td>
<td class="code leading">
<pre class="chroma">
<span class="nx">queue</span> <span class="o">:=</span> <span class="nb">make</span><span class="p">(</span><span class="kd">chan</span> <span class="kt">string</span><span class="p">,</span> <span class="mi">2</span><span class="p">)</span>
<span class="nx">queue</span> <span class="o"><-</span> <span class="s">"one"</span>
<span class="nx">queue</span> <span class="o"><-</span> <span class="s">"two"</span>
<span class="nb">close</span><span class="p">(</span><span class="nx">queue</span><span class="p">)</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
<p>This <code>range</code> iterates over each element as it’s
received from <code>queue</code>. Because we <code>close</code>d the
channel above, the iteration terminates after
receiving the 2 elements.</p>
</td>
<td class="code">
<pre class="chroma">
<span class="k">for</span> <span class="nx">elem</span> <span class="o">:=</span> <span class="k">range</span> <span class="nx">queue</span> <span class="p">{</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">(</span><span class="nx">elem</span><span class="p">)</span>
<span class="p">}</span>
<span class="p">}</span>
</pre>
</td>
</tr>
</table>
<table>
<tr>
<td class="docs">
</td>
<td class="code leading">
<pre class="chroma"><span class="gp">$</span> go run range-over-channels.go
<span class="go">one
</span><span class="go">two</span></pre>
</td>
</tr>
<tr>
<td class="docs">
<p>This example also showed that it’s possible to close
a non-empty channel but still have the remaining
values be received.</p>
</td>
<td class="code empty">
</td>
</tr>
</table>
<p class="next">
Next example: <a href="timers">Timers</a>.
</p>
<p class="footer">
by <a href="https://markmcgranaghan.com">Mark McGranaghan</a> and <a href="https://eli.thegreenplace.net">Eli Bendersky</a> | <a href="https://github.com/mmcgrana/gobyexample">source</a> | <a href="https://github.com/mmcgrana/gobyexample#license">license</a>
</p>
</div>
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</body>
</html>