Sibling Package Imports

Sibling package imports

Seven years after

Since I wrote the answer below, modifying sys.path is still a quick-and-dirty trick that works well for private scripts, but there has been several improvements

• Installing the package (in a virtualenv or not) will give you what you want, though I would suggest using pip to do it rather than using setuptools directly (and using setup.cfg to store the metadata)
• Using the -m flag and running as a package works too (but will turn out a bit awkward if you want to convert your working directory into an installable package).
• For the tests, specifically, pytest is able to find the api package in this situation and takes care of the sys.path hacks for you

So it really depends on what you want to do. In your case, though, since it seems that your goal is to make a proper package at some point, installing through pip -e is probably your best bet, even if it is not perfect yet.

Old answer

As already stated elsewhere, the awful truth is that you have to do ugly hacks to allow imports from siblings modules or parents package from a __main__ module. The issue is detailed in PEP 366. PEP 3122 attempted to handle imports in a more rational way but Guido has rejected it one the account of

The only use case seems to be running scripts that happen
to be living inside a module's directory, which I've always seen as an
antipattern.

(here)

Though, I use this pattern on a regular basis with

# Ugly hack to allow absolute import from the root folder
# whatever its name is. Please forgive the heresy.
if __name__ == "__main__" and __package__ is None:
    from sys import path
    from os.path import dirname as dir

    path.append(dir(path[0]))
    __package__ = "examples"

import api

Here path[0] is your running script's parent folder and dir(path[0]) your top level folder.

I have still not been able to use relative imports with this, though, but it does allow absolute imports from the top level (in your example api's parent folder).

How to import sibling file within a package?

In ui/utils.py, use a relative import.

from . import utils.file

NameChanger itself is likely not in your search path (nor does it need to be). But since NameChanger is a package, the relative import in a module contained in a subpackage of NameChanger should work.

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I originally suggested

from .utils import file

which would only work if utils really had file as a module-level attribute, which is generally not the case for a package.

How to import python modules from sibling directory?

Since there are already many answers on SO for this*, I will focus on question (2). About what is a better code organization:

|- setup.py
|- top_pkg_name
    |- __init__.py
    |- pkg1
        |- __init__.py
    |- pkg2
        |- __init__.py

The (relative) import is done as follows, from inside module_2:

from ..pkg1 import module1 as m1

Alternatively, you can use absolute imports, which refer to the top package name:

from top_pkg_name.pkg1 import module1 as m1

In such an organization, when you want to run any module as a script, you have to use the -m flag:

python -m top_pkg_name.pkg1.module1

For question (3), I'm not sure but it looks like the unittest module adds the folder to path, allowing the imports to happen directly.

*Refer:

1. How do I import a Python script from a sibling directory?
2. Python import module from sibling folder

Import Sibling Packages with __init__.py doesn't work

Before the import sentence, add the following code

import sys
sys.path.append("./")

which adds the current path to workspace, then you can import module successfully.

Here's my project screenshot with the same folder structure as yours.

[ EDIT ]

I assumed your cwd(current working directory) is under the root_folder, like mine. then the sys.path.append("./") should work.

Now turn to the root_Project, add the following code in launch.json:

"env": {
    "PYTHONPATH": "${workspaceFolder}",
},
"cwd": "${workspaceFolder}"

Python extension will search module under root_project, you can directly import the module:

More detailed information please refer to env in debug and Variables.

How to import a Python module from a sibling folder?

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.

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