192 lines
6.9 KiB
Plaintext
Generated
192 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 в примерах: Переменные (Variables)</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 = 'values';
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if (e.key == "ArrowRight") {
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window.location.href = 'constants';
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}
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</script>
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<body>
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<div class="example" id="variables">
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<h2><a href="./">Go в примерах</a>: Переменные (Variables)</h2>
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<table>
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<tr>
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<td class="docs">
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<p>В Go, <em>переменные</em> объявляются явно и используются
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компилятором, например, для проверки корректного
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вызова функции (типы аргументов)</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/BUbDhWP8PV_k" target="_blank"><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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</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><code>var</code> объявляет 1 или более переменных</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">var</span> <span class="nx">a</span> <span class="p">=</span> <span class="s">"initial"</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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</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>Вы можете объявить несколько переменных за раз</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">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>
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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> <span class="nx">c</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 будет определять тип по инициализированной переменной.</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">var</span> <span class="nx">d</span> <span class="p">=</span> <span class="kc">true</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">d</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>Переменные, объявленные без соответствующей инициализации,
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имеют <em>нулевое значение</em>. Например, нулевое значение
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для <code>int</code> равно <code>0</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">var</span> <span class="nx">e</span> <span class="kt">int</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">e</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>В Go существует короткий пператор <code>:=</code> для
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объявления и инициализации переменной.
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Например, <code>var f string = "apple"</code> в короткой записи
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превратится в</p>
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</td>
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<td class="code">
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<div class="highlight"><pre> <span class="nx">f</span> <span class="o">:=</span> <span class="s">"apple"</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">f</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">
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<div class="highlight"><pre><span class="gp">$</span> go run variables.go
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<span class="go">initial</span>
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<span class="go">1 2</span>
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<span class="go">true</span>
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<span class="go">0</span>
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<span class="go">apple</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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<p class="next">
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Следующий пример: <a href="constants">Константы (Constants)</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/variables">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 main() {\u000A');codeLines.push(' var a = \"initial\"\u000A fmt.Println(a)\u000A');codeLines.push(' var b, c int = 1, 2\u000A fmt.Println(b, c)\u000A');codeLines.push(' var d = true\u000A fmt.Println(d)\u000A');codeLines.push(' var e int\u000A fmt.Println(e)\u000A');codeLines.push(' f := \"apple\"\u000A fmt.Println(f)\u000A}\u000A');codeLines.push('');
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</script>
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<script src="site.js" async></script>
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</body>
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</html>
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