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What's up with if name == "main": some random code at the end of module files? Never seen that, why is it used? I understand that it's a guard tha

by roveo 5y ago

What's up with if __name__ == "__main__": some random code at the end of module files? Never seen that, why is it used? I understand that it's a guard that only runs when the module is executed directly, but what is the code put there? For developers to quickly visually test stuff by running the module? Here, for example https://github.com/willmcgugan/rich/blob/master/rich/color.py#L557-L581 https://github.com/willmcgugan/rich/blob/master/rich/color.p...

detaro 5y ago
That clearly prints out a reference of the colors, so yes, as shorthand for devs.
npage97 5y ago
Yea it is there for devs to see different rich features in their console. You can run some examples using the -m flag + the submodule: python -m rich.live python -m rich.markdown # this is actually a markdown to terminal cli https://rich.readthedocs.io/en/stable/live.html https://rich.readthedocs.io/en/stable/live.html https://rich.readthedocs.io/en/stable/markdown.html https://rich.readthedocs.io/en/stable/markdown.html
FreakLegion 5y ago
It's a common pattern as others have said, but this specific version of it is poor practice. The code should be in a function instead of polluting the global namespace (otherwise 'console', 'table', and 'color' end up being shadowed if they're used elsewhere in the file). Keep it clean with e.g.: def main() -> None: pass if __name__ == "__main__": main()
- willm 5y ago
  That is not the case. The code within that block will not be in the namespace if that file is imported. Contrary to your example which will have the main function in the module namespace.
  - FreakLegion 5y ago
    > "if that file is imported" Static analysis doesn't care. The script can be executed directly, so it has to be treated as if it will be. The fact that the code behaves differently between prod and dev use is a smell, not a selling point. I'm saying this in the context of writing modern Python with modern tools. In that context it's a poor practice.

What's up with if __name__ == "__main__": some random code at the end of module files? Never seen that, why is it used? I understand that it's a guard tha

by roveo 5y ago

detaro 5y ago

That clearly prints out a reference of the colors, so yes, as shorthand for devs.

npage97 5y ago

Yea it is there for devs to see different rich features in their console. You can run some examples using the -m flag + the submodule: python -m rich.live python -m rich.markdown # this is actually a markdown to terminal cli https://rich.readthedocs.io/en/stable/live.html https://rich.readthedocs.io/en/stable/live.html https://rich.readthedocs.io/en/stable/markdown.html https://rich.readthedocs.io/en/stable/markdown.html

FreakLegion 5y ago

It's a common pattern as others have said, but this specific version of it is poor practice. The code should be in a function instead of polluting the global namespace (otherwise 'console', 'table', and 'color' end up being shadowed if they're used elsewhere in the file). Keep it clean with e.g.: def main() -> None: pass if __name__ == "__main__": main()

willm 5y ago
That is not the case. The code within that block will not be in the namespace if that file is imported. Contrary to your example which will have the main function in the module namespace.
- FreakLegion 5y ago
  > "if that file is imported" Static analysis doesn't care. The script can be executed directly, so it has to be treated as if it will be. The fact that the code behaves differently between prod and dev use is a smell, not a selling point. I'm saying this in the context of writing modern Python with modern tools. In that context it's a poor practice.