174 lines
5.7 KiB
Plaintext
Generated
174 lines
5.7 KiB
Plaintext
Generated
<!DOCTYPE html>
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<html>
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<head>
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<meta charset="utf-8">
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<title>Go by Example: Multiple Return Values</title>
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<link rel=stylesheet href="site.css">
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<script>
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onkeydown = (e) => {
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<body>
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<div class="example" id="multiple-return-values">
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<h2><a href="./">Go by Example</a>: Multiple Return Values</h2>
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<table>
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<tr>
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<td class="docs">
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<p>Go has built-in support for <em>multiple return values</em>.
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This feature is used often in idiomatic Go, for example
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to return both result and error values from a function.</p>
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</td>
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<td class="code empty leading">
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</td>
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<tr>
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<td class="docs">
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</td>
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<td class="code leading">
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<a href="http://play.golang.org/p/FZoIB5LXQGZ"><img title="Run code" src="play.png" class="run" /></a><img title="Copy code" src="clipboard.png" class="copy" />
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<div class="highlight"><pre><span class="kn">package</span> <span class="nx">main</span>
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</pre></div>
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</td>
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</tr>
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<tr>
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<td class="docs">
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</td>
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<td class="code leading">
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<div class="highlight"><pre><span class="kn">import</span> <span class="s">"fmt"</span>
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</pre></div>
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</td>
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</tr>
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<tr>
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<td class="docs">
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<p>The <code>(int, int)</code> in this function signature shows that
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the function returns 2 <code>int</code>s.</p>
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</td>
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<td class="code leading">
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<div class="highlight"><pre><span class="kd">func</span> <span class="nx">vals</span><span class="p">()</span> <span class="p">(</span><span class="kt">int</span><span class="p">,</span> <span class="kt">int</span><span class="p">)</span> <span class="p">{</span>
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<span class="k">return</span> <span class="mi">3</span><span class="p">,</span> <span class="mi">7</span>
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<span class="p">}</span>
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</pre></div>
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</td>
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</tr>
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<tr>
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<td class="docs">
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</td>
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<td class="code leading">
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<div class="highlight"><pre><span class="kd">func</span> <span class="nx">main</span><span class="p">()</span> <span class="p">{</span>
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</pre></div>
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</td>
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</tr>
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<tr>
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<td class="docs">
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<p>Here we use the 2 different return values from the
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call with <em>multiple assignment</em>.</p>
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</td>
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<td class="code leading">
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<div class="highlight"><pre> <span class="nx">a</span><span class="p">,</span> <span class="nx">b</span> <span class="o">:=</span> <span class="nx">vals</span><span class="p">()</span>
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<span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span><span class="p">(</span><span class="nx">a</span><span class="p">)</span>
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<span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span><span class="p">(</span><span class="nx">b</span><span class="p">)</span>
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</pre></div>
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</td>
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</tr>
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<tr>
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<td class="docs">
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<p>If you only want a subset of the returned values,
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use the blank identifier <code>_</code>.</p>
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</td>
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<td class="code">
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<div class="highlight"><pre> <span class="nx">_</span><span class="p">,</span> <span class="nx">c</span> <span class="o">:=</span> <span class="nx">vals</span><span class="p">()</span>
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<span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span><span class="p">(</span><span class="nx">c</span><span class="p">)</span>
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<span class="p">}</span>
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</pre></div>
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</td>
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</tr>
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</table>
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<table>
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<td class="docs">
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</td>
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<td class="code leading">
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<div class="highlight"><pre><span class="gp">$</span> go run multiple-return-values.go
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<span class="go">3</span>
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<span class="go">7</span>
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<span class="go">7</span>
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</pre></div>
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</td>
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</tr>
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<tr>
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<td class="docs">
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<p>Accepting a variable number of arguments is another nice
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feature of Go functions; we’ll look at this next.</p>
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</td>
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<td class="code empty">
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</td>
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</tr>
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</table>
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<p class="next">
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Next example: <a href="variadic-functions">Variadic Functions</a>.
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</p>
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<p class="footer">
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by <a href="https://markmcgranaghan.com">Mark McGranaghan</a> | <a href="https://github.com/mmcgrana/gobyexample/blob/master/examples/multiple-return-values">source</a> | <a href="https://github.com/mmcgrana/gobyexample#license">license</a>
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</p>
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</div>
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<script>
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var codeLines = [];
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codeLines.push('');codeLines.push('package main\u000A');codeLines.push('import \"fmt\"\u000A');codeLines.push('func vals() (int, int) {\u000A return 3, 7\u000A}\u000A');codeLines.push('func main() {\u000A');codeLines.push(' a, b := vals()\u000A fmt.Println(a)\u000A fmt.Println(b)\u000A');codeLines.push(' _, c := vals()\u000A fmt.Println(c)\u000A}\u000A');codeLines.push('');codeLines.push('');
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