Question

I stumbled over the import of __init__.py in python packages. See posts:

• different import results at different directories
• how to reload a Class in python shell?

I was directed by Nate to very good explanations at this post:

Adding code to __init__.py.

I want to read more about this topic and more related topics. Could anyone suggest further formal documentations or books on the topics? TIA!

Answer 1

I found a very good explanation at:

http://effbot.org/zone/import-confusion.htm#what-does-python-do

and the critical sentence for me was:

When Python imports a module, it first checks the module registry
(sys.modules) to see if the module is already imported. If that’s the
case, Python uses the existing module object as is.