361 lines
18 KiB
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Generated
361 lines
18 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: Директории (Directories)</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 = 'file-paths';
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}
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if (e.key == "ArrowRight") {
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window.location.href = 'temporary-files-and-directories';
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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="directories">
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<h2><a href="./">Go в примерах</a>: Директории (Directories)</h2>
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<table>
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<tr>
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<td class="docs">
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<p>Go имеет несколько полезных функций для работы
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с <em>каталогами</em> в файловой системе.</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/6lC_YCFEXVl" 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="p">(</span>
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<span class="s">"fmt"</span>
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<span class="s">"io/ioutil"</span>
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<span class="s">"os"</span>
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<span class="s">"path/filepath"</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">check</span><span class="p">(</span><span class="nx">e</span> <span class="kt">error</span><span class="p">)</span> <span class="p">{</span>
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<span class="k">if</span> <span class="nx">e</span> <span class="o">!=</span> <span class="kc">nil</span> <span class="p">{</span>
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<span class="nb">panic</span><span class="p">(</span><span class="nx">e</span><span class="p">)</span>
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<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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<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>Создадим новую суб-директорию в текущей рабочей
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папке.</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">err</span> <span class="o">:=</span> <span class="nx">os</span><span class="p">.</span><span class="nx">Mkdir</span><span class="p">(</span><span class="s">"subdir"</span><span class="p">,</span> <span class="mo">0755</span><span class="p">)</span>
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<span class="nx">check</span><span class="p">(</span><span class="nx">err</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>Когда мы создаем временную директорию, хорошим
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тоном является удалить ее через <code>defer</code>.
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<code>os.RemoveAll</code> удалит директорию и все, что в ней
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находится (по аналогии с <code>rm -rf</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="k">defer</span> <span class="nx">os</span><span class="p">.</span><span class="nx">RemoveAll</span><span class="p">(</span><span class="s">"subdir"</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>Функция-помощник для создания нового пустого файла.</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">createEmptyFile</span> <span class="o">:=</span> <span class="kd">func</span><span class="p">(</span><span class="nx">name</span> <span class="kt">string</span><span class="p">)</span> <span class="p">{</span>
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<span class="nx">d</span> <span class="o">:=</span> <span class="p">[]</span><span class="nb">byte</span><span class="p">(</span><span class="s">""</span><span class="p">)</span>
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<span class="nx">check</span><span class="p">(</span><span class="nx">ioutil</span><span class="p">.</span><span class="nx">WriteFile</span><span class="p">(</span><span class="nx">name</span><span class="p">,</span> <span class="nx">d</span><span class="p">,</span> <span class="mo">0644</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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<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="nx">createEmptyFile</span><span class="p">(</span><span class="s">"subdir/file1"</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>Мы можем создать иерархию из директорий, включая все
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родительские, с помощью <code>MkdirAll</code>. Это является аналогом
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команды <code>mkdir -p</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">err</span> <span class="p">=</span> <span class="nx">os</span><span class="p">.</span><span class="nx">MkdirAll</span><span class="p">(</span><span class="s">"subdir/parent/child"</span><span class="p">,</span> <span class="mo">0755</span><span class="p">)</span>
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<span class="nx">check</span><span class="p">(</span><span class="nx">err</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 leading">
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<div class="highlight"><pre> <span class="nx">createEmptyFile</span><span class="p">(</span><span class="s">"subdir/parent/file2"</span><span class="p">)</span>
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<span class="nx">createEmptyFile</span><span class="p">(</span><span class="s">"subdir/parent/file3"</span><span class="p">)</span>
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<span class="nx">createEmptyFile</span><span class="p">(</span><span class="s">"subdir/parent/child/file4"</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>ReadDir</code> перечисляет содержимое каталогов,
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возвращая срез объектов <code>os.FileInfo</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">c</span><span class="p">,</span> <span class="nx">err</span> <span class="o">:=</span> <span class="nx">ioutil</span><span class="p">.</span><span class="nx">ReadDir</span><span class="p">(</span><span class="s">"subdir/parent"</span><span class="p">)</span>
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<span class="nx">check</span><span class="p">(</span><span class="nx">err</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 leading">
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<div class="highlight"><pre> <span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span><span class="p">(</span><span class="s">"Listing subdir/parent"</span><span class="p">)</span>
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<span class="k">for</span> <span class="nx">_</span><span class="p">,</span> <span class="nx">entry</span> <span class="o">:=</span> <span class="k">range</span> <span class="nx">c</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">" "</span><span class="p">,</span> <span class="nx">entry</span><span class="p">.</span><span class="nx">Name</span><span class="p">(),</span> <span class="nx">entry</span><span class="p">.</span><span class="nx">IsDir</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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<tr>
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<td class="docs">
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<p><code>Chdir</code> позволяет изменить текущую рабочую
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директорию, по аналогии с <code>cd</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">err</span> <span class="p">=</span> <span class="nx">os</span><span class="p">.</span><span class="nx">Chdir</span><span class="p">(</span><span class="s">"subdir/parent/child"</span><span class="p">)</span>
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<span class="nx">check</span><span class="p">(</span><span class="nx">err</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>Теперь мы увидим содержимое директории
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<code>subdir/parent/child</code>, когда запросим листинг
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<em>текущей</em> директории.</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">c</span><span class="p">,</span> <span class="nx">err</span> <span class="p">=</span> <span class="nx">ioutil</span><span class="p">.</span><span class="nx">ReadDir</span><span class="p">(</span><span class="s">"."</span><span class="p">)</span>
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<span class="nx">check</span><span class="p">(</span><span class="nx">err</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 leading">
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<div class="highlight"><pre> <span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span><span class="p">(</span><span class="s">"Listing subdir/parent/child"</span><span class="p">)</span>
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<span class="k">for</span> <span class="nx">_</span><span class="p">,</span> <span class="nx">entry</span> <span class="o">:=</span> <span class="k">range</span> <span class="nx">c</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">" "</span><span class="p">,</span> <span class="nx">entry</span><span class="p">.</span><span class="nx">Name</span><span class="p">(),</span> <span class="nx">entry</span><span class="p">.</span><span class="nx">IsDir</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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<tr>
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<td class="docs">
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<p>Вернемся в начало</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">err</span> <span class="p">=</span> <span class="nx">os</span><span class="p">.</span><span class="nx">Chdir</span><span class="p">(</span><span class="s">"../../.."</span><span class="p">)</span>
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<span class="nx">check</span><span class="p">(</span><span class="nx">err</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>Мы также можем <em>рекурсивно</em> обойти каталог, включая
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все его подкаталоги. <code>Walk</code> принимает функцию обратного
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вызова для обработки каждого файла или каталога,
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которые посетили.</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">fmt</span><span class="p">.</span><span class="nx">Println</span><span class="p">(</span><span class="s">"Visiting subdir"</span><span class="p">)</span>
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<span class="nx">err</span> <span class="p">=</span> <span class="nx">filepath</span><span class="p">.</span><span class="nx">Walk</span><span class="p">(</span><span class="s">"subdir"</span><span class="p">,</span> <span class="nx">visit</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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<tr>
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<td class="docs">
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<p><code>visit</code> вызывается для каждого найденного элемента в <code>filepath.Walk</code>.</p>
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</td>
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<td class="code">
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<div class="highlight"><pre><span class="kd">func</span> <span class="nx">visit</span><span class="p">(</span><span class="nx">p</span> <span class="kt">string</span><span class="p">,</span> <span class="nx">info</span> <span class="nx">os</span><span class="p">.</span><span class="nx">FileInfo</span><span class="p">,</span> <span class="nx">err</span> <span class="kt">error</span><span class="p">)</span> <span class="kt">error</span> <span class="p">{</span>
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<span class="k">if</span> <span class="nx">err</span> <span class="o">!=</span> <span class="kc">nil</span> <span class="p">{</span>
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<span class="k">return</span> <span class="nx">err</span>
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<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">" "</span><span class="p">,</span> <span class="nx">p</span><span class="p">,</span> <span class="nx">info</span><span class="p">.</span><span class="nx">IsDir</span><span class="p">())</span>
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<span class="k">return</span> <span class="kc">nil</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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||
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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 directories.go
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<span class="go">Listing subdir/parent</span>
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<span class="go"> child true</span>
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<span class="go"> file2 false</span>
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<span class="go"> file3 false</span>
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<span class="go">Listing subdir/parent/child</span>
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<span class="go"> file4 false</span>
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<span class="go">Visiting subdir</span>
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<span class="go"> subdir true</span>
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<span class="go"> subdir/file1 false</span>
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<span class="go"> subdir/parent true</span>
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<span class="go"> subdir/parent/child true</span>
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<span class="go"> subdir/parent/child/file4 false</span>
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<span class="go"> subdir/parent/file2 false</span>
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<span class="go"> subdir/parent/file3 false</span>
|
||
</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="temporary-files-and-directories">Временные файлы и директории (Temporary Files and Directories)</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/directories">source</a> | <a href="https://github.com/mmcgrana/gobyexample#license">license</a>
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||
</p>
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||
</div>
|
||
<script>
|
||
var codeLines = [];
|
||
codeLines.push('');codeLines.push('package main\u000A');codeLines.push('import (\u000A \"fmt\"\u000A \"io/ioutil\"\u000A \"os\"\u000A \"path/filepath\"\u000A)\u000A');codeLines.push('func check(e error) {\u000A if e != nil {\u000A panic(e)\u000A }\u000A}\u000A');codeLines.push('func main() {\u000A');codeLines.push(' err := os.Mkdir(\"subdir\", 0755)\u000A check(err)\u000A');codeLines.push(' defer os.RemoveAll(\"subdir\")\u000A');codeLines.push(' createEmptyFile := func(name string) {\u000A d := []byte(\"\")\u000A check(ioutil.WriteFile(name, d, 0644))\u000A }\u000A');codeLines.push(' createEmptyFile(\"subdir/file1\")\u000A');codeLines.push(' err = os.MkdirAll(\"subdir/parent/child\", 0755)\u000A check(err)\u000A');codeLines.push(' createEmptyFile(\"subdir/parent/file2\")\u000A createEmptyFile(\"subdir/parent/file3\")\u000A createEmptyFile(\"subdir/parent/child/file4\")\u000A');codeLines.push(' c, err := ioutil.ReadDir(\"subdir/parent\")\u000A check(err)\u000A');codeLines.push(' fmt.Println(\"Listing subdir/parent\")\u000A for _, entry := range c {\u000A fmt.Println(\" \", entry.Name(), entry.IsDir())\u000A }\u000A');codeLines.push(' err = os.Chdir(\"subdir/parent/child\")\u000A check(err)\u000A');codeLines.push(' c, err = ioutil.ReadDir(\".\")\u000A check(err)\u000A');codeLines.push(' fmt.Println(\"Listing subdir/parent/child\")\u000A for _, entry := range c {\u000A fmt.Println(\" \", entry.Name(), entry.IsDir())\u000A }\u000A');codeLines.push(' err = os.Chdir(\"../../..\")\u000A check(err)\u000A');codeLines.push(' fmt.Println(\"Visiting subdir\")\u000A err = filepath.Walk(\"subdir\", visit)\u000A}\u000A');codeLines.push('func visit(p string, info os.FileInfo, err error) error {\u000A if err != nil {\u000A return err\u000A }\u000A fmt.Println(\" \", p, info.IsDir())\u000A return nil\u000A}\u000A');codeLines.push('');
|
||
</script>
|
||
<script src="site.js" async></script>
|
||
</body>
|
||
</html>
|