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<div class="example" id="range">
<h2><a href="./">Go by Example</a>: Range</h2>
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<p><em>range</em> itera sobre elementos de uma variedade
de estrutura de dados. Aqui será demonstrado como
utilizá-lo com algumas das estruturas de dados já
apresentadas.</p>
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<a target="_blank" href="https://go.dev/play/p/0jbhU_qHfKO"><img title="Executar código em nova aba" src="play.png" class="run" /></a><img title="Copiar código" src="clipboard.png" class="copy" />
<pre class="chroma"><span class="kn">package</span> <span class="nx">main</span>
</pre>
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<pre class="chroma"><span class="kn">import</span> <span class="s">&#34;fmt&#34;</span>
</pre>
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<pre class="chroma"><span class="kd">func</span> <span class="nf">main</span><span class="p">()</span> <span class="p">{</span>
</pre>
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<p>Aqui é utilizado o <code>range</code> para somar os números
de um slice. Funciona da mesma forma em arrays.</p>
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<pre class="chroma">
<span class="nx">nums</span> <span class="o">:=</span> <span class="p">[]</span><span class="kt">int</span><span class="p">{</span><span class="mi">2</span><span class="p">,</span> <span class="mi">3</span><span class="p">,</span> <span class="mi">4</span><span class="p">}</span>
<span class="nx">sum</span> <span class="o">:=</span> <span class="mi">0</span>
<span class="k">for</span> <span class="nx">_</span><span class="p">,</span> <span class="nx">num</span> <span class="o">:=</span> <span class="k">range</span> <span class="nx">nums</span> <span class="p">{</span>
<span class="nx">sum</span> <span class="o">+=</span> <span class="nx">num</span>
<span class="p">}</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">(</span><span class="s">&#34;soma:&#34;</span><span class="p">,</span> <span class="nx">sum</span><span class="p">)</span>
</pre>
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<p><code>range</code> tanto em arrays quanto em slices fornece
chave e valor; ou índice e valor para cada entrada.
No exemplo acima não foi necessário o índice, então
foi ignorado com identificador vazio <code>_</code>.
Algumas vezes, entretanto, os índices serão necessários.</p>
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<pre class="chroma">
<span class="k">for</span> <span class="nx">i</span><span class="p">,</span> <span class="nx">num</span> <span class="o">:=</span> <span class="k">range</span> <span class="nx">nums</span> <span class="p">{</span>
<span class="k">if</span> <span class="nx">num</span> <span class="o">==</span> <span class="mi">3</span> <span class="p">{</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">(</span><span class="s">&#34;índice:&#34;</span><span class="p">,</span> <span class="nx">i</span><span class="p">)</span>
<span class="p">}</span>
<span class="p">}</span>
</pre>
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<p><code>range</code> em mapas itera sobre os pares de chave/valor.</p>
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<pre class="chroma">
<span class="nx">kvs</span> <span class="o">:=</span> <span class="kd">map</span><span class="p">[</span><span class="kt">string</span><span class="p">]</span><span class="kt">string</span><span class="p">{</span><span class="s">&#34;a&#34;</span><span class="p">:</span> <span class="s">&#34;apple&#34;</span><span class="p">,</span> <span class="s">&#34;b&#34;</span><span class="p">:</span> <span class="s">&#34;banana&#34;</span><span class="p">}</span>
<span class="k">for</span> <span class="nx">k</span><span class="p">,</span> <span class="nx">v</span> <span class="o">:=</span> <span class="k">range</span> <span class="nx">kvs</span> <span class="p">{</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nf">Printf</span><span class="p">(</span><span class="s">&#34;%s -&gt; %s\n&#34;</span><span class="p">,</span> <span class="nx">k</span><span class="p">,</span> <span class="nx">v</span><span class="p">)</span>
<span class="p">}</span>
</pre>
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<p><code>range</code> pode iterar apenas sobre as chaves de um mapa.</p>
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<pre class="chroma">
<span class="k">for</span> <span class="nx">k</span> <span class="o">:=</span> <span class="k">range</span> <span class="nx">kvs</span> <span class="p">{</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">(</span><span class="s">&#34;key:&#34;</span><span class="p">,</span> <span class="nx">k</span><span class="p">)</span>
<span class="p">}</span>
</pre>
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<p><code>range</code> em strings itera sobre pontos de código Unicode.
O primeiro valor é o byte de índice de início da <code>rune</code>,
e o segundo, da própria <code>rune</code>.
Veja a seção <a href="strings-and-runes">Strings and Runes</a>
para mais detalhes.</p>
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<pre class="chroma">
<span class="k">for</span> <span class="nx">i</span><span class="p">,</span> <span class="kt">rune</span> <span class="o">:=</span> <span class="k">range</span> <span class="s">&#34;go&#34;</span> <span class="p">{</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">(</span><span class="nx">i</span><span class="p">,</span> <span class="kt">rune</span><span class="p">)</span>
<span class="p">}</span>
<span class="p">}</span>
</pre>
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<pre class="chroma"><span class="gp">$</span> go run range.go
<span class="go">soma: 9
</span><span class="go">índice: 1
</span><span class="go">a -&gt; apple
</span><span class="go">b -&gt; banana
</span><span class="go">key: a
</span><span class="go">key: b
</span><span class="go">0 103
</span><span class="go">1 111</span></pre>
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<p class="next">
Próximo exemplo: <a href="functions">Functions</a>.
</p>
<p class="footer">
Por <a href="https://markmcgranaghan.com">Mark McGranaghan</a> e <a href="https://eli.thegreenplace.net">Eli Bendersky</a> | traduzido por <a href="https://github.com/lucassauro">Lucassauro</a> | <a href="https://github.com/lucassauro/gobyexample">contribua</a> | <a href="https://github.com/mmcgrana/gobyexample#license">licença</a>
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