Python Library - Module Not Found - python

I'm making a python library and i want to be able to run the code i'm developing, in another folder i have a python file, but I get the error: ModuleNotFoundError: No module named
this is my folder structure
.
└── project
└── library_directory
├── __init__.py
└── main.py
└── examples_directory
├── __init__.py
└── code_directory
├── __init__.py
└── test.py
init.py from library_directory
from library_directory.main import Class
test.py file
from library_directory import Class
when I run test.py file it says: ModuleNotFoundError: No module named 'fpdf_table'
if i put test.py file at project level this configuration of init and test works, but i want to run the test.py in the code_directory because i will have a lot of files and don't want 15+ single files at project level
.
└── project
└── library_directory
├── __init__.py
└── main.py
└── examples_directory
├── __init__.py
└── code_directory
├── __init__.py
└── test.py
i already tried absolute and relative imports but they don't work

Im not sure if this is the correct solution, but you can try this:
In your test module:
import sys
sys.path.insert(0, '/Your_project_root_path'
Now can access to the packages in the root directory.
I took this solution from here.

Your library_directory folder is a Python package. Within the package, each .py file is a module.
In your library_directory/init.py file, insert the line from .main import Class. Now you have a package called "library_directory", which has a module called "Main", and a class called "Class".
Now, in your environment variables, create a user variable called PYTHONPATH and add to this, the path to your project directory.
When you import in your project file, you should import using the structure: from package.module import class, or in your case: from library_directory.main import Class. The python interpreter will be able to find the package due to being in your PYTHONPATH and the init file directory means Python will recognise it as a package.
(You may wish to rename "library_directory" to be a bit more project specific)

Related

Properly doing relative imports in python

I always have the same problem and I finally want to get rid of it. My folder structure looks like this
project
├── scipts
│ └── folder
│ └── file.py
└── submodules
└── lab_devices
└── optical_devices
└── __init__.py
└── powermeter_driver.py
I now want to include the powermeter_driver.py in file.py. So what I do in the file.py is:
from submodules.lab_devices.optical_devices.powermeter_driver import PowermeterDriver
but this gives ModuleNotFoundError: No module named 'submodules'. I don't want to use
import sys
sys.path.insert(0, '../submodules')
Is there an easy workaround?
The imports will be resolved correctly if you run the script in the correct way, which is from the parent directory and using the -m switch. So you should cd in the parent folder, add __init__.py files as in:
project
├── scripts
└── __init__.py
│ └── folder
└── __init__.py
│ └── file.py
└── submodules
└── __init__.py
└── lab_devices
└── __init__.py
└── optical_devices
└── __init__.py
└── powermeter_driver.py
so that python knows these are packages then run
python -m scripts.folder.file # note no .py
In file.py you can then use the absolute import as you are cause submodules will be detected as a package. You should indeed avoid hacking the sys.path by all means.
You need to consider that if you write from submodules.... this is an absolute import. It means Python starts searching for the submodules in all directories in sys.path. Python usually adds your current working directory as first item to sys.path, so if you cd to your project directory and then run it as a module using python -m it could work.
Of course absolute imports suck if you have files in a relative location to each other. I've had similar issues and I've created an experimental, new import library ultraimport that allows to do file system based imports. It could solve your issue if you are willing to add a new library for this.
Instead of:
from submodules.lab_devices.optical_devices.powermeter_driver import PowermeterDriver
In file.py you would then write:
import ultraimport
PowermeterDriver = ultraimport('__dir__/../../submodules/lab_devices/optical_devices/powermeter_driver.py', 'PowermeterDriver')
The file path is relative to file.py and thus this will always work, no matter how you run your code or what is in sys.path.
One caveat when importing scripts like this is if they contain further relative imports. ultraimport has a builtin preprocessor to rewrite subsequent relative imports so they continue to work.

attempted relative import with no known parent package errors when trying to import from local folder?

I have this folder structure in my Python project:
MY-PROJECT
.vscode
myfolder1
├── .venv
├── myconfig.yaml
├── myproject.toml
├── poetry.lock
└── myfolder2
├── __init__.py
├── __main__.py
├── config.py
└── mycode.py
From mycode.py I am trying to do a from . import __version__ and from .config import configuration. My understanding is that it should work as mycode.py is in the same folder as __init__.py and config.py, but I get the following error:
attempted relative import with no known parent package
File "Volumes/myvolume/myfiles/MY-PROJECT/myfolder1/myfolder2/mycode.py", line 12, in <module>
from . import __version__
Python version is 3.9.7 (using poetry).
Any ideas on what might be wrong?
I have found the answer :)
Instead of ., if you manually add the folder name the code works as expected.
from myfolder2 import __version__

How do I structure my python project such that my test files can import the packages in the root folder?

I would like to integrate pytest into my workflow. I made a following folder structure:
myproject
├── venv
└── src
├── __init__.py
├── foo
│ ├── __init__.py
│ └── bar.py
└── tests
├── __init__.py
└── test_bar.py
I would like to be able to import the namespace from the foo package so that I can write test scripts in the tests folder. Whenever I try to run pytest, or pytest --import-mode append I always get the following error:
ModuleNotFoundError: No module named 'foo'
I found this similar question here but adding the __init__.py files to the tests and the src folder does not solve the issue.
Does this have to do with the PYTHONPATH system variable? This folder structure works perfectly if I run the __main__.py from the src folder, but fails when I want to use pytest. Is there a way to do this without having to mess with PYTHONPATH or are there automated ways to edit the system variable?

Project module not found outside virtualenv

My project has basically an architecture like this:
src
├── __init__.py
├── main.py
└── core
├── __init__.py
├── module1.py
└── module2.py
All __init__.py files are empty, in main.py I have a from src.core.module1 import stuff and I am running main.py from the src folder.
When I'm running it from my project virtual environment everything works fine, but outside of the virtual environment I have an ImportError: no module named src.core.module1. I cannot understand why, because this module is in the project, not related to the Python environment packages...
(Windows / Python 2.7.14)
Try from core.module1 import stuff. You should not import src since you are in that location with your main.py already.

Import module fails from the Python radish-bdd executable

I am trying to run tests in radish, a Behaviour Driven Development environment for Python, but I am failing to do even the easiest of things.
I have this structure:
.
├── features
│   └── my.feature
└── radish
├── __init__.py
├── harness
│   ├── __init__.py
│   └── main.py
└── steps.py
When I do
python -c "import radish.harness"
from my working dir ".", things are fine.
When I do the same ("import radish.harness" or "import harness") in the file steps.py, I'm getting this when calling the command "radish features" from the same directory:
ModuleNotFoundError: No module named 'radish.harness'
or
ModuleNotFoundError: No module named 'harness'
The radish-bdd quick start guide quick start guide says about this:
How does radish find my python modules? radish imports all python
modules inside the basedir. Per default the basedir points to
$PWD/radish which in our case is perfectly fine.
Indeed a file placed in the radish directory will be imported automatically, but I am unable to import anything from within these files (apart from system libraries).
Can anyone advise me on how to import modules? I'm lost. It seems that my python knowledge on module import isn't helping.
I suggest you to move the 'harness' directory at the same level as 'features' and 'radish' directory.
.
├── features
│ └── my.feature
├── radish
│ ├── __init__.py
│ └── steps.py
└── harness
├── __init__.py
└── main.py
If you call radish from your working dir (".") like this:
radish -b radish features/my.feature
Then you can import your "harness" module from steps.py like this
import harness
That will work because in this case Python will find your "harness" module as it is in the current directory.

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