mirror of https://github.com/python/cpython
24 lines
887 B
ReStructuredText
24 lines
887 B
ReStructuredText
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:mod:`__main__` --- Top-level script environment
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================================================
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.. module:: __main__
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:synopsis: The environment where the top-level script is run.
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``'__main__'`` is the name of the scope in which top-level code executes.
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A module's __name__ is set equal to ``'__main__'`` when read from
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standard input, a script, or from an interactive prompt.
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A module can discover whether or not it is running in the main scope by
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checking its own ``__name__``, which allows a common idiom for conditionally
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executing code in a module when it is run as a script or with ``python
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-m`` but not when it is imported:
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if __name__ == "__main__":
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# execute only if run as a script
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main()
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For a package, the same effect can be achieved by including a
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``__main__.py`` module, the contents of which will be executed when the
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module is run with ``-m``.
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