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

Dealing with global variables

We have already seen how to use global variables to share information between different functions within a module. We've seen how to define globals as top-level variables within a module, causing them to be initialized the first time the module is imported, and we have also seen how to use the global statement within a function to allow that function to access and change the value of a global variable.

In this section, we will build on this knowledge to learn how to share global variables between modules. When creating a package, you often need to define variables that can be accessed or changed by any module within that package. Sometimes, you also need to make a variable available to Python code outside your package. Let's take a look at how this can be done.

Create a new directory named globtest, and create an empty package initialization file inside this directory to make it a Python package. Then, create a file inside this directory named, and...