Book Image

Secret Recipes of the Python Ninja

Book Image

Secret Recipes of the Python Ninja

Overview of this book

This book covers the unexplored secrets of Python, delve into its depths, and uncover its mysteries. You’ll unearth secrets related to the implementation of the standard library, by looking at how modules actually work. You’ll understand the implementation of collections, decimals, and fraction modules. If you haven’t used decorators, coroutines, and generator functions much before, as you make your way through the recipes, you’ll learn what you’ve been missing out on. We’ll cover internal special methods in detail, so you understand what they are and how they can be used to improve the engineering decisions you make. Next, you’ll explore the CPython interpreter, which is a treasure trove of secret hacks that not many programmers are aware of. We’ll take you through the depths of the PyPy project, where you’ll come across several exciting ways that you can improve speed and concurrency. Finally, we’ll take time to explore the PEPs of the latest versions to discover some interesting hacks.
Table of Contents (17 chapters)
Title Page
Copyright and Credits
Packt Upsell
Foreword
Contributors
Preface
Index

Improving Python collections


This section is designed to showcase different ways to improve your coding methodology by using the various Python collections available to you. Not every collections datatype is represented, but some interesting use cases are explored for certain containers.

How to do it...

The following examples are separated by the particular collection they utilize. iPython will be used to interactively create these examples.

Default dictionaries

  1. For this example (book_catalog.py), we will create a simplified ordering scheme for book categories; the default_factory will be an anonymous function that returns a string:
    • The line 1 simply imports the collections module, allowing access to the defaultdict class.
    • The line 2 creates an instance of defaultdict. The argument for the factory is a simple string indicating that the selected item doesn't exist.
    • The lines 3line 6 create items for the dictionary.
    • The line 7 prints the default representation of the dictionary.
    • The line 8 is a...