How to properly use relative or absolute imports in Python modules?

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Usage of relative imports in Python has one drawback, you will not be able to run the modules as standalones anymore because you will get an exception: ValueError: Attempted relative import in non-package

# /test.py: just a sample file importing foo module
import foo
...

# /foo/foo.py:
from . import bar
...
if __name__ == "__main__":
   pass

# /foo/bar.py: a submodule of foo, used by foo.py
from . import foo
...
if __name__ == "__main__":
   pass

How should I modify the sample code in order to be able to execute all: test.py, foo.py and bar.py

I'm looking for a solution that works with python 2.6+ (including 3.x).

python-module module python-import package python
6 Answers

You need __init__.py in each folder.

Relative import works only when you do:

python test.py

test.py imports foo.py and foo.py can relative import anything from the folder of test.py and above.

You can't do:

cd foo
python foo.py
python bar.py

It will never work.

You can try the sys.path.append or sys.path.insert solution but you gonna screw up the paths and you'll have problems with the f=open(filename).

user_6140360
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