Book Image

Modular Programming with Python

By : Erik Westra
Book Image

Modular Programming with Python

By: Erik Westra

Overview of this book

Python has evolved over the years and has become the primary choice of developers in various fields. The purpose of this book is to help readers develop readable, reliable, and maintainable programs in Python. Starting with an introduction to the concept of modules and packages, this book shows how you can use these building blocks to organize a complex program into logical parts and make sure those parts are working correctly together. Using clearly written, real-world examples, this book demonstrates how you can use modular techniques to build better programs. A number of common modular programming patterns are covered, including divide-and-conquer, abstraction, encapsulation, wrappers and extensibility. You will also learn how to test your modules and packages, how to prepare your code for sharing with other people, and how to publish your modules and packages on GitHub and the Python Package Index so that other people can use them. Finally, you will learn how to use modular design techniques to be a more effective programmer.
Table of Contents (16 chapters)
Modular Programming with Python
About the Author
About the Reviewer

Tweaking imports using sys.path

When you use the import command, the Python interpreter has to search for the module or package you want to import. It does this by looking through the module search path, which is a list of the various directories where modules or packages can be found. The module search path is stored in sys.path, and the Python interpreter will check the directories in this list one after another until the desired module or package is found.

When the Python interpreter starts, it initializes the module search path with the following directories:

  • The directory containing the currently-executing script, or the current directory if you are running the Python interactive interpreter in a terminal window

  • Any directories listed in the PYTHONPATH environment variable

  • The contents of the interpreter's site-packages directory, including any modules referred to by path configuration files within the site-packages directory


    The site-packages directory is used to hold the various third...