如何从同级文件夹导入 Python 模块？

Question

I have gone through many Python relative import questions but I can't understand the issue/get it to work.

My directory structure is:

Driver.py

A/
      Account.py
      __init__.py

B/
      Test.py
      __init__.py

Driver.py

from B import Test

Account.py

class Account:
def __init__(self):
    self.money = 0

Test.py

from ..A import Account

When I try to run:

python Driver.py

I get the error

Traceback (most recent call last):

from B import Test

File "B/Test.py", line 1, in <module> from ..A import Account

ValueError: Attempted relative import beyond toplevel package

Answer 1

This is happening because A and B are independent, unrelated, packages as far as Python is concerned.

Create a __init__.py in the same directory as Driver.py and everything should work as expected.

Answer 2

In my case adding __init__.py was not enough. You also have to append the path of the parent directory if you get module not found error.

root :
 |
 |__SiblingA:
 |    \__A.py
 |     
 |__SiblingB:
 |      \_ __init__.py
 |      \__B.py
 |

To import B.py from A.py, you have to do the following

import sys
  
# append the path of the parent directory
sys.path.append("..")

from SiblingB import B
print("B is successfully imported!")

Answer 3

The reason for

ValueError: Attempted relative import beyond toplevel package

is that A is the same directory level as Driver.py . Hence, ..A in from..A import Account is beyond top-level package.

You can solve this by create a new folder named AandB together with __init__py in this new folder, and then move A and B folders into AandB folder. The directory structure is as following：

Correspondingly, the content in Driver.py should be modified as from AandB.B import Test .