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<span id="main-top-level-script-environment"></span><h1><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 notranslate"><span class="pre">__main__</span></code></a> — Top-level script environment<a class="headerlink" href="#module-__main__" title="Permalink to this headline">¶</a></h1>
<hr class="docutils" />
<p><code class="docutils literal notranslate"><span class="pre">'__main__'</span></code> is the name of the scope in which top-level code executes.
A module’s __name__ is set equal to <code class="docutils literal notranslate"><span class="pre">'__main__'</span></code> when read from
standard input, a script, or from an interactive prompt.</p>
<p>A module can discover whether or not it is running in the main scope by
checking its own <code class="docutils literal notranslate"><span class="pre">__name__</span></code>, which allows a common idiom for conditionally
executing code in a module when it is run as a script or with <code class="docutils literal notranslate"><span class="pre">python</span>
<span class="pre">-m</span></code> but not when it is imported:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="k">if</span> <span class="vm">__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>
</pre></div>
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<p>For a package, the same effect can be achieved by including a
<code class="docutils literal notranslate"><span class="pre">__main__.py</span></code> module, the contents of which will be executed when the
module is run with <code class="docutils literal notranslate"><span class="pre">-m</span></code>.</p>
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