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<section id="module-builtins">
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<span id="builtins-built-in-objects"></span><h1><a class="reference internal" href="#module-builtins" title="builtins: The module that provides the built-in namespace."><code class="xref py py-mod docutils literal notranslate"><span class="pre">builtins</span></code></a> --- 内建对象<a class="headerlink" href="#module-builtins" title="永久链接至标题">¶</a></h1>
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<p>大多数应用程序通常不会显式访问此模块，但在提供与内置值同名的对象的模块中可能很有用，但其中还需要内置该名称。例如，在一个想要实现 <a class="reference internal" href="functions.html#open" title="open"><code class="xref py py-func docutils literal notranslate"><span class="pre">open()</span></code></a> 函数的模块中，它包装了内置的 <a class="reference internal" href="functions.html#open" title="open"><code class="xref py py-func docutils literal notranslate"><span class="pre">open()</span></code></a> ，这个模块可以直接使用:</p>
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<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">builtins</span>
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<span class="k">def</span> <span class="nf">open</span><span class="p">(</span><span class="n">path</span><span class="p">):</span>
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<span class="n">f</span> <span class="o">=</span> <span class="n">builtins</span><span class="o">.</span><span class="n">open</span><span class="p">(</span><span class="n">path</span><span class="p">,</span> <span class="s1">'r'</span><span class="p">)</span>
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<span class="k">return</span> <span class="n">UpperCaser</span><span class="p">(</span><span class="n">f</span><span class="p">)</span>
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<span class="k">class</span> <span class="nc">UpperCaser</span><span class="p">:</span>
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<span class="w"> </span><span class="sd">'''Wrapper around a file that converts output to upper-case.'''</span>
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<span class="bp">self</span><span class="o">.</span><span class="n">_f</span> <span class="o">=</span> <span class="n">f</span>
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<span class="k">return</span> <span class="bp">self</span><span class="o">.</span><span class="n">_f</span><span class="o">.</span><span class="n">read</span><span class="p">(</span><span class="n">count</span><span class="p">)</span><span class="o">.</span><span class="n">upper</span><span class="p">()</span>
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<span class="c1"># ...</span>
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</pre></div>
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<p>作为一个实现细节，大多数模块都将名称 <code class="docutils literal notranslate"><span class="pre">__builtins__</span></code> 作为其全局变量的一部分提供。 <code class="docutils literal notranslate"><span class="pre">__builtins__</span></code> 的值通常是这个模块或者这个模块的值 <a class="reference internal" href="stdtypes.html#object.__dict__" title="object.__dict__"><code class="xref py py-attr docutils literal notranslate"><span class="pre">__dict__</span></code></a> 属性。由于这是一个实现细节，因此 Python 的替代实现可能不会使用它。</p>
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最后更新于 12月 09, 2024.
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