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

Implementing a reusable package


This section includes a lot of source code. Remember that you don't have to type it all in by hand; a complete copy of the quantities package is provided as part of the sample code that can be downloaded for this chapter.

Start by creating the directory named quantities to hold our new package. Inside this directory, create a new file named This module will hold our implementation of a quantity—that is, a value together with its associated units.

While you don't need to understand object-oriented programming techniques to work through this book, this is the one place where we need to use object-oriented programming. This is because we want the user to be able to print a quantity directly, and the only way to do that in Python is to use objects. Don't worry, though—this code is very straightforward, and we'll take it one step at a time.

In the module, enter the following Python code:

class Quantity(object):
    def __init__(self, value...