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

Designing a reusable package

Let's now take what we've learned and apply it to the design and implementation of a useful Python package. In the previous chapter, we looked at the concept of encapsulating a recipe using a Python module. Part of each recipe is the notion of an ingredient, which has three parts:

  • The name of the ingredient

  • How much of the ingredient is needed

  • The units in which the ingredient is measured

If we want to work with ingredients, we need to be able to handle units properly. For example, adding 1.5 kilograms to 750 grams involves more than adding the numbers 1.5 and 750—you have to know how to convert these values from one unit to another.

In the case of recipes, there are a number of rather unusual conversions that you need to support. For example, did you know that three teaspoons of sugar equals one tablespoon of sugar? To handle these types of conversions, let's write a unit conversion library.

Our unit converter will have to be aware of all the standard units used in...