201 lines
6.9 KiB
Plaintext
Generated
201 lines
6.9 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: Functions</title>
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<link rel=stylesheet href="site.css">
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</head>
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<script>
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onkeydown = (e) => {
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if (e.key == "ArrowLeft") {
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window.location.href = 'range';
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}
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if (e.key == "ArrowRight") {
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window.location.href = 'multiple-return-values';
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}
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}
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</script>
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<body>
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<div class="example" id="functions">
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<h2><a href="./">Go by Example</a>: Functions</h2>
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<table>
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<tr>
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<td class="docs">
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<p><em>Functions</em> are central in Go. We’ll learn about
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functions with a few different examples.</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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<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/hzGUvK6iJNm"><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>Here’s a function that takes two <code>int</code>s and returns
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their sum as an <code>int</code>.</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">plus</span><span class="p">(</span><span class="nx">a</span> <span class="kt">int</span><span class="p">,</span> <span class="nx">b</span> <span class="kt">int</span><span class="p">)</span> <span class="kt">int</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>Go requires explicit returns, i.e. it won’t
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automatically return the value of the last
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expression.</p>
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</td>
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<td class="code leading">
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<div class="highlight"><pre> <span class="k">return</span> <span class="nx">a</span> <span class="o">+</span> <span class="nx">b</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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<p>When you have multiple consecutive parameters of
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the same type, you may omit the type name for the
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like-typed parameters up to the final parameter that
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declares the type.</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">plusPlus</span><span class="p">(</span><span class="nx">a</span><span class="p">,</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="kt">int</span> <span class="p">{</span>
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<span class="k">return</span> <span class="nx">a</span> <span class="o">+</span> <span class="nx">b</span> <span class="o">+</span> <span class="nx">c</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>Call a function just as you’d expect, with
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<code>name(args)</code>.</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">res</span> <span class="o">:=</span> <span class="nx">plus</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span> <span class="mi">2</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="s">"1+2 ="</span><span class="p">,</span> <span class="nx">res</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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</td>
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<td class="code">
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<div class="highlight"><pre> <span class="nx">res</span> <span class="p">=</span> <span class="nx">plusPlus</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span> <span class="mi">2</span><span class="p">,</span> <span class="mi">3</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="s">"1+2+3 ="</span><span class="p">,</span> <span class="nx">res</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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<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="gp">$</span> go run functions.go
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<span class="go">1+2 = 3</span>
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<span class="go">1+2+3 = 6</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>There are several other features to Go functions. One is
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multiple return values, which we’ll look at 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="multiple-return-values">Multiple Return Values</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/functions">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 plus(a int, b int) int {\u000A');codeLines.push(' return a + b\u000A}\u000A');codeLines.push('func plusPlus(a, b, c int) int {\u000A return a + b + c\u000A}\u000A');codeLines.push('func main() {\u000A');codeLines.push(' res := plus(1, 2)\u000A fmt.Println(\"1+2 =\", res)\u000A');codeLines.push(' res = plusPlus(1, 2, 3)\u000A fmt.Println(\"1+2+3 =\", res)\u000A}\u000A');codeLines.push('');codeLines.push('');
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</script>
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</body>
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</html>
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