uTools-Manuals/docs/python/__main__.html

<div class="body" role="main"><div class="section" id="module-__main__"><h1><span class="yiyi-st" id="yiyi-10">29.4. </span><span class="yiyi-st" id="yiyi-11"><a class="reference internal" href="#module-__main__" title="__main__: The environment where the top-level script is run."><code class="xref py py-mod docutils literal"><span class="pre">__main__</span></code></a> — Top-level script environment</span></h1><p><span class="yiyi-st" id="yiyi-12"><code class="docutils literal"><span class="pre">'__main__'</span></code>是一个作用域的名称，顶层代码在这个作用域中执行。</span><span class="yiyi-st" id="yiyi-13">当从标准输入，脚本或交互式提示读取时，模块的__name__设置为等于<code class="docutils literal"><span class="pre">'__main__'</span></code>。</span></p><p><span class="yiyi-st" id="yiyi-14">模块可以通过检查它自己的<code class="docutils literal"><span class="pre">__name__</span></code>来发现它是否在主作用域中运行，这允许在作为脚本运行时或在<code class="docutils literal"> <span class="pre">python</span> <span class="pre">-m</span></code>但不导入时：</span></p><pre><code class="language-python"><span></span><span class="k">if</span> <span class="n">__name__</span> <span class="o">==</span> <span class="s2">"__main__"</span><span class="p">:</span>
    <span class="c1"># execute only if run as a script</span>
    <span class="n">main</span><span class="p">()</span>
</code></pre><p><span class="yiyi-st" id="yiyi-15">对于包，通过包括<code class="docutils literal"><span class="pre">__main__.py</span></code>模块可以实现相同的效果，当模块以<code class="docutils literal"><span class="pre">-m</span></code>运行时，将执行该模块的内容。</span></p></div></div>