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

Running modules from the command line

In Chapter 2, Writing Your First Modular Program, we saw your system's main program is often named and typically has the following structure:

def main():

if __name__ == "__main__":

The __name__ global variable will be set to the value "__main__" by the Python interpreter when the user runs your program. This has the effect of calling your main() function when the program is run.

There is nothing special about the program, however; it's just another Python source file. You can take advantage of this to make your Python modules executable from the command line.

Consider, for example, the following module, which we will call

def double(n):
    return n * 2

if __name__ == "__main__":
    print("double(3) =", double(3))

This module defines some functionality, in this case a function named double(), and then uses the if __name__ == "__main__" trick to demonstrate and test the module's functionality when it is run from...