从子 package 导入模块不起作用

Question

My file structure is

project/
    __init__.py
    features/
        __init__.py
        CompareText.py
    tests/
        test.py

in test.py I am trying to import CompareText

from project.features import CompareText

I get an error of:

 ModuleNotFoundError: No module named 'features'`

I checked the documentation and I think my import statement is correct. How can I fix it?

Answer 1

Your import statement is supposed to look like this: (But make sure your working directory is the same directory as your project folder is located during execution)

    from project.features import CompareText

This is supposed to work if your current path while executing the script has the project folder

If you execute it while inside project folder you can use:

    from .features import CompareText

Hope this helps!

Answer 2

Add an __init__ file in test . Your project directory should look like this:

project/
    __init__.py
    features/
        __init__.py
        CompareText.py
    tests/
        __init__.py
        test.py

Then in project/tests/test.py the following import statement will work:

from ..features import CompareText

Oh, and this will still raise an error if you try to run it directly. In the question you said you tried to import it like this:

from project.features import CompareText

This will only work if the parent directory of project is in Python's module search path. So, if you want to run the tests directly then modify the module search path as needed (See: sys.path ).

Answer 3

I assume you are running test.py as a script. test.py needs to find the project package and two ways to do that are to make your project installable or to hack sys.path .

Installable

First, change your directory structure a bit so that project is a subdirectory of some anonymous directory you happen to be using for development. If you are checking this stuff into source control, it needs to be written so that it can be checked out anywhere. Move tests down one directory.

mydevdir/
    setup.py
    project/
        __init__.py
        features/
            __init__.py
            CompareText.py
    tests/
        test.py

How write a setup.py . This can get quite complicated. You can read Building and Distributing Packages with Setuptools and lookup other resources on the net, but a minimalist setup.py is

#!/usr/bin/env python

from setuptools import setup, find_packages

setup(name='project',
      version='0.1',
      description='This is project: project',
      packages=find_packages(),
     )

Now, while in mydevdir do python setup.py develop . Or you can actually produce an install package and put it in a virtual env for test.

Hack sys.path

It may be easier to hack paths in test.py . Note that this will need to be undone if you make project installable later. Just add to the top of test.py

import sys
from pathlib import Path
sys.path.insert(0, str(Path(__file__).absolute().parents[2]))

This puts the parent directory in the python path and now project will be found on import. It runs the risk that a.py file in the same directory as project can mask an installed module. If you have a local csv.py and you import csv , you'd get the local.