A python “module” is a single namespace, with a collection of values:
- functions
- constants
- class definitions
- etc.
A module usually corresponds to a single file: something.py
A package is essentially a module, except it can have other modules (and indeed other packages) inside it.
A package usually corresponds to a directory with a file in it called __init__.py and any number of python files or other package directories:
a_package
__init__.py
module_a.py
a_sub_package
__init__.py
module_b.py
The __init__.py can be totally empty or it can have python code in it. The code will be run when the package is imported. Modules inside packages are not automatically imported. So, with the above structure:
import a_package
will run the code in a_package/__init__.py.
Any names defined in the __init__.py will be available in:
a_package.a_name
but:
a_package.module_a
will not exist. To get submodules, you need to explicitly import them:
import a_package.module_a
An example setup.py:
from setuptools import setup
setup(
name='PackageName',
version='0.1.0',
author='An Awesome Coder',
author_email='[email protected]',
packages=['package_name', 'package_name.test'],
scripts=['bin/script1','bin/script2'],
url='http://pypi.python.org/pypi/PackageName/',
license='LICENSE.txt',
description='An awesome package that does something',
long_description=open('README.txt').read(),
install_requires=[
"Django >= 1.1.1",
"pytest",
],
)
With a setup.py script defined, setuptools can do a lot:
Build a source distribution (a tar archive of all the files needed to build and install the package):
python setup.py sdist
Build from source:
python setup.py build
And install:
python setup.py install
Install in "develop" or "editable" mode:
python setup.py develop
or
pip install -e .