python - relative path not working even with __init__.py

Question

I know that there are plenty of similar questions on stack overflow. But the common answer doesn't seem to be working for me.

I have a file structure like this

  proj/
       lib/
          __init__.py
          aa.py
          bb.py
          test/
               __init__.py
               aa_test.py

I figured that if I include the code in my test.py

import lib.aa

or

from lib import aa

I would be able to reference the modules in the lib/ directory. But that did not work.

So I tried to add to path, and it adds it correctly:

os.environ["PATH"] += ":%s" % os.path.abspath(os.path.join("..",""))
print os.environ["PATH"]

but even now when I try the import statements above... I keep getting the error

ImportError: No module named aa

or

ImportError: Importing from non-package <Something...>

Is there something obvious I am missing?

Is there a way to check if I have configured my __init__.py files correctly, or to see my package hierarchy?

Answer 1

You need to update your sys.path, which is where python looks for modules, as opposed to your system's path in the current environment, which is what os.environ["PATH"] is referring to.

Example:

import os, sys
sys.path.insert(0, os.path.abspath(".."))
import aa

After doing this, you can use your functions in aa like this: aa.myfunc()

There's some more information in the accepted answer for python: import a module from a directory