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

Optional imports

Try opening the Python interactive interpreter and entering the following command:

import nonexistent_module

The interpreter will return the following error message:

ImportError: No module named 'nonexistent_module'

This shouldn't be a surprise to you; you may have even seen this error in your own programs if you made a typo within an import statement.

The interesting thing about this error is that it doesn't just apply where you've made a typo. You can also use this to test if a module or package is available on this particular computer, for example:

    import numpy
    has_numpy = True
except ImportError:
    has_numpy = False

You can then use this to have your program take advantage of the module if it is present, or do something else if the module or package isn't available, like this:

if has_numpy:
    array = numpy.zeros((num_rows, num_cols), dtype=numpy.int32)
    array = []
    for row in num_rows:

In this example, we check to see if...