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

Looking at the collections – extended module


If you search PyPI, you will find the collections-extended module (https://pypi.python.org/pypi/collections-extended/1.0.0). Collections-extended expands the number of collections types available.

The following classes are included:

  • bag: It is equivalent to a multiset, bags build upon the default set container by allowing multiple instances of the bag's elements.

A bag (also called a multiset in other languages) generalizes the concept of a set so that it allows multiple instances of elements. For example, {a, a, b}, and {a, b} are different bags, but part of the same set. Only hashable elements can be used in a bag. An important point about bags is the multiplicity of elements. Multiplicity is the the number of instances of an element in a specific bag, that is, how many duplicate values exist in a bag.

  • setlist: This creates an ordered, indexed collection with unique elements. setlist is used to create an object that is similar to anordered set,...