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

Local imports

In Chapter 3, Using Modules and Packages, we introduced the concept of a global namespace, and showed how the import statement adds the name of the imported module or package into the global namespace. This description was actually a slight oversimplification. In fact, the import statement adds the imported module or package to the current namespace, which may or may not be the global namespace.

In Python, there are two namespaces: the global namespace and the local namespace. The global namespace is where all the top-level definitions in your source file are stored. For example, consider the following Python module:

import random
import string

def set_length(length):
    global _length
    _length = length

def make_name():
    global _length

    letters = []
    for i in range(length):
    return "".join(letters)

When you import this Python module, you will have added four entries to the global namespace: random, string...