Multilevel relative import

问题:

Multilevel relative import

I have following folder structure

top\
   __init__.py
   util\
      __init__.py
      utiltest.py
   foo\
      __init__.py
      foo.py
      bar\
         __init__.py
         foobar.py

I want to access from foobar.py the module utiltest.py. I tried following relative import, but this doesn't work: from ...util.utiltest import *

I always get ValueError: Attempted relative import beyond toplevel package

How to do such a multileve relative import?

回答1:

You must import foobar from the parent folder of top:

import top.foo.bar.foobar

This tells Python that top is the top level package. Relative imports are possible only inside a package.

回答2:

I realize this is an old question, but I feel the accepted answer likely misses the main issue with the questioner's code. It's not wrong, strictly speaking, but it gives a suggestion that only coincidentally happens to work around the real issue.

That real issue is that the foobar.py file in top\foo\bar is being run as a script. When a (correct!) relative import is attempted, it fails because the Python interpreter doesn't understand the package structure.

The best fix for this is to run foobar.py not by filename, but instead to use the -m flag to the interpreter to tell it to run the top.foo.bar.foobar module. This way Python will know the main module it's loading is in a package, and it will know exactly where the relative import is referring.