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variables.html
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<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Go by Example 中文版: 变量</title>
<link rel=stylesheet href="site.css">
</head>
<script>
onkeydown = (e) => {
if (e.key == "ArrowLeft") {
window.location.href = 'values';
}
if (e.key == "ArrowRight") {
window.location.href = 'constants';
}
}
</script>
<body>
<div class="example" id="variables">
<h2><a href="./">Go by Example 中文版</a>: 变量</h2>
<table>
<tr>
<td class="docs">
<p>在 Go 中，<em>变量</em> 需要显式声明，并且在函数调用等情况下，
编译器会检查其类型的正确性。</p>
</td>
<td class="code empty leading">
</td>
</tr>
<tr>
<td class="docs">
</td>
<td class="code leading">
<a href="https://play.studygolang.com/p/7c8w-lGxib6"><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><code>var</code> 声明 1 个或者多个变量。</p>
</td>
<td class="code leading">
<pre class="chroma">
<span class="kd">var</span> <span class="nx">a</span> <span class="p">=</span> <span class="s">"initial"</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">(</span><span class="nx">a</span><span class="p">)</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
<p>你可以一次性声明多个变量。</p>
</td>
<td class="code leading">
<pre class="chroma">
<span class="kd">var</span> <span class="nx">b</span><span class="p">,</span> <span class="nx">c</span> <span class="kt">int</span> <span class="p">=</span> <span class="mi">1</span><span class="p">,</span> <span class="mi">2</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">(</span><span class="nx">b</span><span class="p">,</span> <span class="nx">c</span><span class="p">)</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
<p>Go 会自动推断已经有初始值的变量的类型。</p>
</td>
<td class="code leading">
<pre class="chroma">
<span class="kd">var</span> <span class="nx">d</span> <span class="p">=</span> <span class="kc">true</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">(</span><span class="nx">d</span><span class="p">)</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
<p>声明后却没有给出对应的初始值时，变量将会初始化为 <em>零值</em> 。
例如，<code>int</code> 的零值是 <code>0</code>。</p>
</td>
<td class="code leading">
<pre class="chroma">
<span class="kd">var</span> <span class="nx">e</span> <span class="kt">int</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">(</span><span class="nx">e</span><span class="p">)</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
<p><code>:=</code> 语法是声明并初始化变量的简写，
例如 <code>var f string = "short"</code> 可以简写为右边这样。</p>
</td>
<td class="code">
<pre class="chroma">
<span class="nx">f</span> <span class="o">:=</span> <span class="s">"short"</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">(</span><span class="nx">f</span><span class="p">)</span>
<span class="p">}</span>
</pre>
</td>
</tr>
</table>
<table>
<tr>
<td class="docs">
</td>
<td class="code">
<pre class="chroma"><span class="gp">$</span> go run variables.go
<span class="go">initial
</span><span class="go">1 2
</span><span class="go">true
</span><span class="go">0
</span><span class="go">short</span></pre>
</td>
</tr>
</table>
<p class="next">
下一个例子: <a href="constants.html">常量</a>
</p>
<p class="footer">
<a href="https://twitter.com/mmcgrana">@mmcgrana</a> 和<a href="https://eli.thegreenplace.net">Eli Bendersky</a>编写 | <a href="https://github.com/gobyexample-cn">gobyexample-cn</a> 翻译 | <a href="https://github.com/gobyexample-cn/gobyexample/issues">反馈</a> | <a href="https://github.com/gobyexample-cn/gobyexample">源码</a> | <a href="https://github.com/mmcgrana/gobyexample#license">license</a> </p>
</p>
</div>
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</html>