Python Packages

last modified March 15, 2024

Python packages tutorial shows how to work with packages in Python. Packages are namespace containers for modules.

Python Package

A Python package is a collection of Python modules. Packages help organize related modules into a single directory hierarchy. Packages are created by adding a special init.py file to a directory.

Creating a Simple Package

This example shows how to create a basic Python package.

mypackage/init.py

This file makes the directory a Python package

version = ‘1.0’

main.py

#!/usr/bin/python

import mypackage

print(mypackage.version)

We create a package called mypackage with an init.py file. The file can be empty or contain initialization code.

Package with Modules

This example shows a package with multiple modules.

mypackage/greet.py

def say_hello(): print(“Hello from greet module”)

main.py

#!/usr/bin/python

from mypackage.greet import say_hello

say_hello()

We add a greet.py module to our package and import its function in main.py.

Importing Package Contents

Different ways to import package contents.

main.py

#!/usr/bin/python

import mypackage.greet from mypackage import greet from mypackage.greet import say_hello

mypackage.greet.say_hello() greet.say_hello() say_hello()

The example shows three ways to import and use package contents.

all in init.py

Using all to control what gets imported with from package import *.

mypackage/init.py

all = [‘greet’]

main.py

#!/usr/bin/python

from mypackage import *

greet.say_hello()

The all list defines which modules are imported when using from package import *.

Subpackages

Creating and using subpackages.

mypackage/subpkg/init.py

Subpackage initialization

mypackage/subpkg/utils.py

def helper():
    print("Helper function from utils")

main.py

#!/usr/bin/python

from mypackage.subpkg.utils import helper

helper()

We create a subpackage subpkg with its own init.py and a utils.py module.

Installing Packages with pip

Installing third-party packages using pip.

Terminal

$ pip install requests $ pip install numpy pandas –user $ pip install -r requirements.txt

The example shows common pip commands for installing Python packages.

Creating a Setup.py

Creating a distributable package with setup.py.

setup.py

from setuptools import setup, find_packages

setup( name=“mypackage”, version=“0.1”, packages=find_packages(), install_requires=[ ‘requests>=2.25.1’, ], )

The setup.py file defines package metadata and dependencies.

Relative Imports

Using relative imports within a package.

mypackage/subpkg/mod.py

from ..greet import say_hello

def mod_func(): say_hello() print(“From mod module”)

The example shows how to use relative imports with .. notation.

Namespace Packages

Creating namespace packages without init.py files.

ns_pkg/pkg1/mod1.py

def ns_func(): print(“Namespace package function”)

main.py

#!/usr/bin/python

from ns_pkg.pkg1.mod1 import ns_func

ns_func()

Python 3.3+ supports namespace packages that don’t require init.py.

Package Data Files

Including non-Python files in packages.

setup.py

from setuptools import setup

setup( name=“mypackage”, version=“1.0”, package_data={ ‘mypackage’: [‘data/*.txt’], }, )

The example shows how to include data files in your package distribution.

Source

Python Packages Documentation

In this article we have worked with Python packages.

Author

My name is Jan Bodnar, and I am a passionate programmer with extensive programming experience. I have been writing programming articles since 2007. To date, I have authored over 1,400 articles and 8 e-books. I possess more than ten years of experience in teaching programming.

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