Download own module with pip, "No module named ..."

Question

I am in the process of building my own Python module, just to get a hang of how it works. My Python is decent, but I have never build or submitted any packages before.

I followed a guide on Python Hosted as well as the official setuptools documentation and this article on python.org. However, I still can't get this to work.

The package structure, with three modules (FileHelpers, TypeHelpers, XmlHelpers), looks like this:

PyLT3/
|- .git/
|- .idea/
|- setup.py
|- __init__.py
|- README.rst
|- LICENSE.txt
|- .gitignore
|- FileHelpers.py
|- TypeHelpers.py
|- XmlHelpers.py

Contents of setup.py:

from setuptools import setup, find_packages

setup(
    name='PyLT3',
    version='0.1.3',
    description='A collection of helper functions and NLP scripts',
    long_description='During my time working on the PhD project PreDict, I have written and gathered a bunch of useful functions. They are collected here as part of the PyLT3 package.',
    keywords='nlp xml file-handling helpers',
    packages=find_packages(),
    url='https://github.com/BramVanroy/PyLT3',
    author='Bram Vanroy',
    author_email='[email protected]',
    license='MIT',
    classifiers=[
        'Development Status :: 1 - Planning',
        'Intended Audience :: Developers',
        'Intended Audience :: Science/Research',
        'Topic :: Scientific/Engineering',
        'Topic :: Text Processing',
        'License :: OSI Approved :: MIT License',
        'Programming Language :: Python :: 3.6',
    ],
    project_urls = {
        'Bug Reports': 'https://github.com/BramVanroy/PyLT3/issues',
        'Source': 'https://github.com/BramVanroy/PyLT3',
    },
    python_requires='>=3.6',
)

Contents of MANIFEST.in:

prune .idea/*

With this data, I create a distribution:

python setup.py sdist

And a wheel:

python setup.py bdist_wheel

And the distribution is then uploaded to PyPi:

twine upload dist/*

To test this out, I download the package with pip:

pip install PyLT3

(Also used pip3.) It successfully installs.

But when I then try a simple import PyLT3, I get an error

import PyLT3 

ModuleNotFoundError: No module named 'PyLT3'

This is odd, because pip told me the module was successfully installed. So I went looking for the module, and its *.info is installed in C:\Python\Python36\Lib\site-packages\PyLT3-0.1.3.dist-info. But I am assuming that this is not the actual package but just an info directory. There is no other package (e.g. PyLT3/).

All of this leads me to believe that I did something wrong when packaging. What did I forget?

Answer 1

Your package doesn’t register a package named PyLT3.

Your project stucture should look like this:

PyLT3/  # This is your project directory. Its name is irrelevant from the packaging point of view.
 |- .git/
 |- .idea/
 |- setup.py
 |- README.rst
 |- LICENSE.txt
 |- .gitignore
 |- PyLT3/  # This is directory holds your python package.
     |- __init__.py
     |- FileHelpers.py
     |- TypeHelpers.py
     |- XmlHelpers.py

You can try this locally by running pip install -e . from your project directory. This allows you to validate this works, before you publish.

A personal note: I would also strongly suggest using lower case package and module names, as per PEP8