a module to import modules

[Skaperen]

i am working on a large program that is made of many files the get run as separate processes.  there is a big set of modules that every file needs to import.  i hate having this list duplicate in every file, especially when i need to make changes.  in C i would have one #include file the would #include all the other #include files.  then each C file would #include that one #include file.

what's a good way (or best way) to do this with large projects in Python?

[nilamo]

Maybe a sub-module with all the other files?  In an __init__.py file, you can do all the importing, and optionally have an __all__ defined, so wherever you want those modules, you can do from modules import * and have a very well defined list of what, exactly, is being imported?

[Skaperen]

so if i use the filename __init__.py i don't need to actually import it?  i figured i would need to do from mycommonmodulename import *.  would that be enough?  can i do from whatever import * there, too (not the same names, of course)?

i was planning on using the name "common".  a choice i have used since my Fortran days (on mainframes, before i switched to Assembler for everything, which was before i did C, which was before i am doing Python).

[nilamo]

If you have a folder named "common", and that folder has a file in it named "__init__.py", then you can do import common or from common import *, and the __init__.py will be run.  Inside that file, you can then do all the common importing as a convenience.

Defining __all__ in the top level just determines what, exactly, is imported if you do from common import *, so that import * doesn't HAVE to actually import everything, only the things you actually want exposed outside the module.

[metulburr]

here is a real world example of using dunder init file in a complex project

the import
https://github.com/metulburr/pyroller/bl...ain.py#L14

craps directory content of __init__.py
https://github.com/metulburr/pyroller/bl..._init__.py
It only imports the Craps class in /craps/craps.py but you can add any number of imports to the __init__.py file.