blocks|key|3091433|text|来自python+docs|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|3091434|使用运行Python模块时的|3091435|blockquote|3091436|3091437|python+fibo.py|3091438|模块中的代码将被执行，就像您导入它一样，但__name__设置为"__main__"。这意味着通过在模块的末尾添加以下代码：|style|CODE|3091439|3091440|if+__name__+==+'__main__':
++++#+Running+as+a+script|code-block|syntax|javascript|3091441|您可以将该文件用作脚本和可导入的模块，因为解析命令行的代码仅在该模块作为“主”文件执行时才会运行|3091442|entityMap|0|LINK|mutability|MUTABLE|url|http://docs.python.org/dev/tutorial/modules.html#executing-modules-as-scripts^0|9|4|0|0|0|0|0|0|L|8|W|A|0|0|0|0^^$0|@$1|2|3|4|5|6|7|14|8|@]|9|@$A|15|B|16|1|17]]|C|$]]|$1|D|3|E|5|6|7|18|8|@]|9|@]|C|$]]|$1|F|3|-4|5|G|7|19|8|@]|9|@]|C|$]]|$1|H|3|-4|5|6|7|1A|8|@]|9|@]|C|$]]|$1|I|3|J|5|6|7|1B|8|@]|9|@]|C|$]]|$1|K|3|L|5|6|7|1C|8|@$A|1D|B|1E|M|N]|$A|1F|B|1G|M|N]]|9|@]|C|$]]|$1|O|3|-4|5|6|7|1H|8|@]|9|@]|C|$]]|$1|P|3|Q|5|R|7|1I|8|@]|9|@]|C|$S|T]]|$1|U|3|V|5|6|7|1J|8|@]|9|@]|C|$]]|$1|W|3|-4|5|6|7|1K|8|@]|9|@]|C|$]]]|X|$Y|$5|Z|10|11|C|$12|13]]]]

<p>from python <a href="http://docs.python.org/dev/tutorial/modules.html#executing-modules-as-scripts" rel="noreferrer">docs</a>:</p>

<blockquote>
  <p>When you run a Python module with</p>
  
  <p>python fibo.py </p>
  
  <p>the code in the module will be
  executed, just as if you imported it,
  but with the <code>__name__</code> set to
  <code>"__main__"</code>. That means that by adding
  this code at the end of your module:</p>
</blockquote>

<pre><code>if __name__ == '__main__':
    # Running as a script
</code></pre>

<p>you can make the file usable as a script as well as an importable module, because the code that parses the command line only runs if the module is executed as the “main” file</p>


blocks|key|3304349|text|正如@bobince所指出的：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3304350|3304351|如果您是由python+-m+somemodule调用的模块，则您也将是__main__|blockquote|offset|length|style|CODE|3304352|3304353|3304354|假设您有一个Python文件bar.py和一个空__init__.py，它们都在名为foo的文件夹中|3304355|$+tree
.
└──+foo
++++├──+__init__.py
++++└──+bar.py

$+cat+foo/__init__.py|code-block|syntax|javascript|3304356|下面的Python代码块是foo/bar.py的内容。|3304357|使用__name__+(不工作)|3304358|print('Code+executed+as+a+%25s'+%25+'script'+if+__name__+==+'__main__'+else+'module')|3304359|这将产生：|3304360|$+python+foo/bar.py
Code+executed+as+a+script

$+python+-m+foo.bar
Code+executed+as+a+script|3304361|解决方案1:使用vars()和sys.modules|3304362|import+sys
mod_name+=+vars(sys.modules[__name__])['__package__']
print('Code+executed+as+a+'+%2B+('module+named+%25s'+%25+mod_name+if+mod_name+else+'script'))|3304363|3304364|$+python+foo/bar.py
Code+executed+as+a+module+named+foo

$+python+-m+foo.bar
Code+executed+as+a+script|3304365|解决方案2:在模块导入时使用try-except块|3304366|import+sys
try:
++++import+foo
++++print('Code+executed+as+a+module')
except+ImportError:
++++print('Code+executed+as+a+script')
++++#+Code+will+fail+here,+but+you+can+still+print+a+comprehensive+error+message+before+exiting:
++++print('Usage:+python+-m+foo.bar')
++++sys.exit()|3304367|3304368|$+python+foo/bar.py
Code+executed+as+a+module

$+python+-m+foo.bar
Code+executed+as+a+script
Usage:+python+-m+foo.bar|3304369|entityMap|0|LINK|mutability|MUTABLE|url|https://docs.python.org/3.7/library/functions.html#vars|1|https://docs.python.org/3.7/library/sys.html#sys.modules^0|0|0|5|K|10|8|0|0|0|E|6|O|B|16|3|0|0|D|A|0|2|8|0|0|0|0|8|6|F|B|8|6|0|F|B|1|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|1Q|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|1R|8|@]|9|@]|A|$]]|$1|C|3|D|5|E|7|1S|8|@$F|1T|G|1U|H|I]|$F|1V|G|1W|H|I]]|9|@]|A|$]]|$1|J|3|-4|5|6|7|1X|8|@]|9|@]|A|$]]|$1|K|3|-4|5|6|7|1Y|8|@]|9|@]|A|$]]|$1|L|3|M|5|6|7|1Z|8|@$F|20|G|21|H|I]|$F|22|G|23|H|I]|$F|24|G|25|H|I]]|9|@]|A|$]]|$1|N|3|O|5|P|7|26|8|@]|9|@]|A|$Q|R]]|$1|S|3|T|5|6|7|27|8|@$F|28|G|29|H|I]]|9|@]|A|$]]|$1|U|3|V|5|6|7|2A|8|@$F|2B|G|2C|H|I]]|9|@]|A|$]]|$1|W|3|X|5|P|7|2D|8|@]|9|@]|A|$Q|R]]|$1|Y|3|Z|5|6|7|2E|8|@]|9|@]|A|$]]|$1|10|3|11|5|P|7|2F|8|@]|9|@]|A|$Q|R]]|$1|12|3|13|5|6|7|2G|8|@$F|2H|G|2I|H|I]|$F|2J|G|2K|H|I]]|9|@$F|2L|G|2M|1|2N]|$F|2O|G|2P|1|2Q]]|A|$]]|$1|14|3|15|5|P|7|2R|8|@]|9|@]|A|$Q|R]]|$1|16|3|Z|5|6|7|2S|8|@]|9|@]|A|$]]|$1|17|3|18|5|P|7|2T|8|@]|9|@]|A|$Q|R]]|$1|19|3|1A|5|6|7|2U|8|@]|9|@]|A|$]]|$1|1B|3|1C|5|P|7|2V|8|@]|9|@]|A|$Q|R]]|$1|1D|3|Z|5|6|7|2W|8|@]|9|@]|A|$]]|$1|1E|3|1F|5|P|7|2X|8|@]|9|@]|A|$Q|R]]|$1|1G|3|-4|5|6|7|2Y|8|@]|9|@]|A|$]]]|1H|$1I|$5|1J|1K|1L|A|$1M|1N]]|1O|$5|1J|1K|1L|A|$1M|1P]]]]

<p>As pointed out by @bobince:</p>

<blockquote>
  <p>You will also be <code>__main__</code> if you are a module invoked by <code>python -m somemodule</code></p>
</blockquote>

<p>Let's suppose you have a Python file <code>bar.py</code> and an empty <code>__init__.py</code>, both inside a folder called <code>foo</code>:</p>

<pre class="lang-sh prettyprint-override"><code>$ tree
.
└── foo
    ├── __init__.py
    └── bar.py

$ cat foo/__init__.py
</code></pre>

<p>The Python code blocks below are the content of <code>foo/bar.py</code>.</p>

<h2>Using <code>__name__</code> (not working)</h2>

<pre class="lang-py prettyprint-override"><code>print('Code executed as a %s' % 'script' if __name__ == '__main__' else 'module')
</code></pre>

<p>This will produce:</p>

<pre class="lang-sh prettyprint-override"><code>$ python foo/bar.py
Code executed as a script

$ python -m foo.bar
Code executed as a script
</code></pre>

<h2>Solution 1: using <a href="https://docs.python.org/3.7/library/functions.html#vars" rel="nofollow noreferrer"><code>vars()</code></a> and <a href="https://docs.python.org/3.7/library/sys.html#sys.modules" rel="nofollow noreferrer"><code>sys.modules</code></a></h2>

<pre class="lang-py prettyprint-override"><code>import sys
mod_name = vars(sys.modules[__name__])['__package__']
print('Code executed as a ' + ('module named %s' % mod_name if mod_name else 'script'))
</code></pre>

<p>This will produce:</p>

<pre class="lang-sh prettyprint-override"><code>$ python foo/bar.py
Code executed as a module named foo

$ python -m foo.bar
Code executed as a script
</code></pre>

<h2>Solution 2: Using a try-except block on module import</h2>

<pre class="lang-py prettyprint-override"><code>import sys
try:
    import foo
    print('Code executed as a module')
except ImportError:
    print('Code executed as a script')
    # Code will fail here, but you can still print a comprehensive error message before exiting:
    print('Usage: python -m foo.bar')
    sys.exit()
</code></pre>

<p>This will produce:</p>

<pre class="lang-sh prettyprint-override"><code>$ python foo/bar.py
Code executed as a module

$ python -m foo.bar
Code executed as a script
Usage: python -m foo.bar
</code></pre>


<p>The question is rather straightforward but not answered by searching. How do I determine in a python script whether this script is imported as a module or run as a script? Is there a difference at all in python?</p>

<p>The problem is, that I want to evaluate the command line parameters only if run as a script, but not if the module is only imported to use it in another script. (I want to be able to use one script as both library and program.) I am afraid the vanilla way would be to build the lib and a second script that uses it, but I'd like to have a second option for small tool/libs. </p>


how do I determine whether a python script is imported as module or run as script?

这个问题很简单，但不能通过搜索来回答。如何在python脚本中确定此脚本是作为模块导入还是作为脚本运行？python有什么不同吗？问题是，我只想在作为脚本运行的情况下评估命令行参数，而不是在导入模块以便在另一个脚本中使用它时进行评估。(我希望能够同时使用一个脚本作为库和程序。)恐怕最好的方法是构建lib和使用它的第二个...

问如何确定python脚本是作为模块导入还是作为脚本运行？
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