gobyexample/public/string-functions
2019-10-15 15:02:01 +03:00

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<h2><a href="./">Go в примерах</a>: Строковые функции (String Functions)</h2>
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<p>Стандартная библиотека пакета <code>strings</code> предоставляет
множество удобных функций для работы со строками. Вот
некоторые из них.</p>
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<a href="http://play.golang.org/p/UeDwSoYepQt" target="_blank"><img title="Run code" src="play.png" class="run" /></a><img title="Copy code" src="clipboard.png" class="copy" />
<div class="highlight"><pre><span class="kn">package</span> <span class="nx">main</span>
</pre></div>
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<div class="highlight"><pre><span class="kn">import</span> <span class="p">(</span>
<span class="s">&quot;fmt&quot;</span>
<span class="nx">s</span> <span class="s">&quot;strings&quot;</span>
<span class="p">)</span>
</pre></div>
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<p>Создаем алиас для функции <code>fmt.Println</code>, т.к. далее мы будем
часто вызывать эту функцию.</p>
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<div class="highlight"><pre><span class="kd">var</span> <span class="nx">p</span> <span class="p">=</span> <span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span>
</pre></div>
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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>
</pre></div>
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<p>Данные функции доступны в пакете <code>strings</code>. Обратите внимание,
что все эти функции из пакета, а не методы строковых объектов.
Это означает, что нам необходимо передать первым аргументом
функции, строку, над которой мы производим операцию. Вы можете
найти больше строковых функций в <a href="http://golang.org/pkg/strings/"><code>официальной документации
к пакету</code></a>.</p>
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<div class="highlight"><pre> <span class="nx">p</span><span class="p">(</span><span class="s">&quot;Contains: &quot;</span><span class="p">,</span> <span class="nx">s</span><span class="p">.</span><span class="nx">Contains</span><span class="p">(</span><span class="s">&quot;test&quot;</span><span class="p">,</span> <span class="s">&quot;es&quot;</span><span class="p">))</span>
<span class="nx">p</span><span class="p">(</span><span class="s">&quot;Count: &quot;</span><span class="p">,</span> <span class="nx">s</span><span class="p">.</span><span class="nx">Count</span><span class="p">(</span><span class="s">&quot;test&quot;</span><span class="p">,</span> <span class="s">&quot;t&quot;</span><span class="p">))</span>
<span class="nx">p</span><span class="p">(</span><span class="s">&quot;HasPrefix: &quot;</span><span class="p">,</span> <span class="nx">s</span><span class="p">.</span><span class="nx">HasPrefix</span><span class="p">(</span><span class="s">&quot;test&quot;</span><span class="p">,</span> <span class="s">&quot;te&quot;</span><span class="p">))</span>
<span class="nx">p</span><span class="p">(</span><span class="s">&quot;HasSuffix: &quot;</span><span class="p">,</span> <span class="nx">s</span><span class="p">.</span><span class="nx">HasSuffix</span><span class="p">(</span><span class="s">&quot;test&quot;</span><span class="p">,</span> <span class="s">&quot;st&quot;</span><span class="p">))</span>
<span class="nx">p</span><span class="p">(</span><span class="s">&quot;Index: &quot;</span><span class="p">,</span> <span class="nx">s</span><span class="p">.</span><span class="nx">Index</span><span class="p">(</span><span class="s">&quot;test&quot;</span><span class="p">,</span> <span class="s">&quot;e&quot;</span><span class="p">))</span>
<span class="nx">p</span><span class="p">(</span><span class="s">&quot;Join: &quot;</span><span class="p">,</span> <span class="nx">s</span><span class="p">.</span><span class="nx">Join</span><span class="p">([]</span><span class="kt">string</span><span class="p">{</span><span class="s">&quot;a&quot;</span><span class="p">,</span> <span class="s">&quot;b&quot;</span><span class="p">},</span> <span class="s">&quot;-&quot;</span><span class="p">))</span>
<span class="nx">p</span><span class="p">(</span><span class="s">&quot;Repeat: &quot;</span><span class="p">,</span> <span class="nx">s</span><span class="p">.</span><span class="nx">Repeat</span><span class="p">(</span><span class="s">&quot;a&quot;</span><span class="p">,</span> <span class="mi">5</span><span class="p">))</span>
<span class="nx">p</span><span class="p">(</span><span class="s">&quot;Replace: &quot;</span><span class="p">,</span> <span class="nx">s</span><span class="p">.</span><span class="nx">Replace</span><span class="p">(</span><span class="s">&quot;foo&quot;</span><span class="p">,</span> <span class="s">&quot;o&quot;</span><span class="p">,</span> <span class="s">&quot;0&quot;</span><span class="p">,</span> <span class="o">-</span><span class="mi">1</span><span class="p">))</span>
<span class="nx">p</span><span class="p">(</span><span class="s">&quot;Replace: &quot;</span><span class="p">,</span> <span class="nx">s</span><span class="p">.</span><span class="nx">Replace</span><span class="p">(</span><span class="s">&quot;foo&quot;</span><span class="p">,</span> <span class="s">&quot;o&quot;</span><span class="p">,</span> <span class="s">&quot;0&quot;</span><span class="p">,</span> <span class="mi">1</span><span class="p">))</span>
<span class="nx">p</span><span class="p">(</span><span class="s">&quot;Split: &quot;</span><span class="p">,</span> <span class="nx">s</span><span class="p">.</span><span class="nx">Split</span><span class="p">(</span><span class="s">&quot;a-b-c-d-e&quot;</span><span class="p">,</span> <span class="s">&quot;-&quot;</span><span class="p">))</span>
<span class="nx">p</span><span class="p">(</span><span class="s">&quot;ToLower: &quot;</span><span class="p">,</span> <span class="nx">s</span><span class="p">.</span><span class="nx">ToLower</span><span class="p">(</span><span class="s">&quot;TEST&quot;</span><span class="p">))</span>
<span class="nx">p</span><span class="p">(</span><span class="s">&quot;ToUpper: &quot;</span><span class="p">,</span> <span class="nx">s</span><span class="p">.</span><span class="nx">ToUpper</span><span class="p">(</span><span class="s">&quot;test&quot;</span><span class="p">))</span>
<span class="nx">p</span><span class="p">()</span>
</pre></div>
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<p>Примеры ниже не относятся к пакету <code>strings</code>, но о них
стоит упомянуть - это механизмы для получения длины
строки и получение символа по индексу.</p>
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<div class="highlight"><pre> <span class="nx">p</span><span class="p">(</span><span class="s">&quot;Len: &quot;</span><span class="p">,</span> <span class="nb">len</span><span class="p">(</span><span class="s">&quot;hello&quot;</span><span class="p">))</span>
<span class="nx">p</span><span class="p">(</span><span class="s">&quot;Char:&quot;</span><span class="p">,</span> <span class="s">&quot;hello&quot;</span><span class="p">[</span><span class="mi">1</span><span class="p">])</span>
<span class="p">}</span>
</pre></div>
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<p>Обратите внимание, что <code>len</code> и индексация выше работают на
уровне байтов. Go использует строки в кодировке UTF-8, так
что это часто полезно как есть. Если вы работаете с
потенциально многобайтовыми символами, вам нужно использовать
операции с кодировкой. Смотрите <a href="https://blog.golang.org/strings">строки, байты, руны и символы
в Go</a> для получения дополнительной
информации.</p>
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<div class="highlight"><pre><span class="gp">$</span> go run string-functions.go
<span class="go">Contains: true</span>
<span class="go">Count: 2</span>
<span class="go">HasPrefix: true</span>
<span class="go">HasSuffix: true</span>
<span class="go">Index: 1</span>
<span class="go">Join: a-b</span>
<span class="go">Repeat: aaaaa</span>
<span class="go">Replace: f00</span>
<span class="go">Replace: f0o</span>
<span class="go">Split: [a b c d e]</span>
<span class="go">ToLower: test</span>
<span class="go">ToUpper: TEST</span>
</pre></div>
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<div class="highlight"><pre><span class="go">Len: 5</span>
<span class="go">Char: 101</span>
</pre></div>
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<p class="next">
Следующий пример: <a href="string-formatting">Форматирование строк (String Formatting)</a>.
</p>
<p class="footer">
by <a href="https://markmcgranaghan.com">Mark McGranaghan</a> | <a href="https://github.com/mmcgrana/gobyexample/blob/master/examples/string-functions">source</a> | <a href="https://github.com/mmcgrana/gobyexample#license">license</a>
<br/>
переведено Nick S. | <a href="https://github.com/badkaktus/gobyexample">исходники</a>
</p>
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