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

How iteration works in Python


In Python, an iterator is an object that represents a stream of data. While iterators are available for containers, sequences in particular always support iteration.

Iterators have the __next__() method available (or the built-in next() function). Calling next() multiple times returns successive items from the data stream. When no more items are available, a StopIteration exception is thrown.

Any class can use an iterator by defining a container.__iter__() method. This method returns an iterator object, typically just self. This object is necessary to support the iterator protocol. Different types of iteration can be supported, with each one providing a specific iterator request. For example, a tree structure could support both breadth-first and depth-first traversals.

The iterator protocol mentioned previously actually comprises two methods: iterator.__next__() and iterator.__iter__(). (Notice that __iter__() has a different class compared to the one above.)

As...