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