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I often see the construct if __name__ == '__main__' in Python code. For example, the queens.py demo in the Python repository ends with these two lines: if __name__ == "__main__": main() Ho...
#3: Nominated for promotion
by
Alexei
·
2022-02-13T11:43:16Z (almost 3 years ago)
#2: Post edited
by
Alexei
·
2021-10-21T17:17:05Z (about 3 years ago)
added relevant tag
#1: Initial revision
by
J-hen
·
2021-10-21T15:55:07Z (about 3 years ago)
What is the purpose of `if __name__ == '__main__'`?
I often see the construct `if __name__ == '__main__'` in Python code. For example, the [`queens.py` demo in the Python repository][queens] ends with these two lines:
```python
if __name__ == "__main__":
main()
```
However, the [`beer.py` demo][beer] does not. Both run just fine and display things in the console. Moreover, if I remove the `if __name__ == "__main__"` line in `queens.py` (and unindent the call of the `main()` function), it still works, nothing changed. When code is non-functional, I'd rather remove it…
So what's the purpose of that construct? When it is useful, and when is it not?
[queens]: https://github.com/python/cpython/blob/311910b31a4bd94dc79298388b7cb65ca5546438/Tools/demo/queens.py
[beer]: https://github.com/python/cpython/blob/311910b31a4bd94dc79298388b7cb65ca5546438/Tools/demo/beer.py