__all__
is very good - it helps guide import statements without automatically importing modules
http://docs.python.org/tutorial/modules.html#importing-from-a-package
using __all__
and import *
is redundant, only __all__
is needed
I think one of the most powerful reasons to use import *
in an __init__.py
to import packages is to be able to refactor a script that has grown into multiple scripts without breaking an existing application. But if you're designing a package from the start. I think it's best to leave __init__.py
files empty.
for example:
foo.py - contains classes related to foo such as fooFactory, tallFoo, shortFoo
then the app grows and now it's a whole folder
foo/
__init__.py
foofactories.py
tallFoos.py
shortfoos.py
mediumfoos.py
santaslittlehelperfoo.py
superawsomefoo.py
anotherfoo.py
then the init script can say
__all__ = ['foofactories', 'tallFoos', 'shortfoos', 'medumfoos',
'santaslittlehelperfoo', 'superawsomefoo', 'anotherfoo']
# deprecated to keep older scripts who import this from breaking
from foo.foofactories import fooFactory
from foo.tallfoos import tallFoo
from foo.shortfoos import shortFoo
so that a script written to do the following does not break during the change:
from foo import fooFactory, tallFoo, shortFoo