What is "__name__" and ......

Erik Max Francis max at alcyone.com
Sun Mar 2 05:35:18 CET 2003


Alonde wrote:

> I don't understand "__name__" and "__main__" and
> everything between the __ and __
> 
> What does
> 
>         if __name == "__main__":

__name__ is the name of the current module.  If this is equal to the
string "__main__" then the module is being executed directly; otherwise
it's being imported.

Watch:

max at oxygen:~/tmp% cat > name.py
print __name__
^D
max at oxygen:~/tmp% python name.py # run the script directly
__main__
max at oxygen:~/tmp% python
Python 2.2.2 (#2, Oct 14 2002, 17:32:20) 
[GCC egcs-2.91.66 19990314/Linux (egcs-1.1.2 release)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import name # import it
name
>>> 

So the canonical

	if __name__ == '__main__': ...

test is to see whether the script is being executed directly instead of
imported.

-- 
 Erik Max Francis / max at alcyone.com / http://www.alcyone.com/max/
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