如何使用这个简单的包避免“在没有已知父包的情况下尝试相对导入”？

Question

Inside packagetest/ , I have these four files:

• __init__.py :

   class TestError(Exception): pass

• __main__.py :

   from . import TestError from .abc import defgh from .ijk.lmn import opq

• abc/__init__.py :

   def defgh(): pass

• ijk/lmn.py :

   def opq(): pass

When running __main__.py , I get this error:

File "D:\\packagetest_ main _.py", line 1, in
from . import TestError
ImportError: attempted relative import with no known parent package

Why does from . import TestError from . import TestError generate an error here?

How to solve this problem here and modify the code as little as possible?

I've already read Relative imports in Python 3 but I don't see how to modify my code here to make it work.

Answer 1

The article ImportError: attempted relative import with no known parent package provides several solutions to this problem and explain how relative import works.

One solution that works for me is to move everything in a parent directory parent/ :

parent/
  |- test.py
  |- packagetest/
       |- __init__.py
       |- __main__.py
       |- abc/
           |- __init__.py
       |- ijk/
           |- lmn.py

Then import the package inside parent/test.py :

import packagetest

and then it works.