Book Image

The Python Workshop - Second Edition

By : Corey Wade, Mario Corchero Jiménez, Andrew Bird, Dr. Lau Cher Han, Graham Lee
4.7 (3)
Book Image

The Python Workshop - Second Edition

4.7 (3)
By: Corey Wade, Mario Corchero Jiménez, Andrew Bird, Dr. Lau Cher Han, Graham Lee

Overview of this book

Python is among the most popular programming languages in the world. It’s ideal for beginners because it’s easy to read and write, and for developers, because it’s widely available with a strong support community, extensive documentation, and phenomenal libraries – both built-in and user-contributed. This project-based course has been designed by a team of expert authors to get you up and running with Python. You’ll work though engaging projects that’ll enable you to leverage your newfound Python skills efficiently in technical jobs, personal projects, and job interviews. The book will help you gain an edge in data science, web development, and software development, preparing you to tackle real-world challenges in Python and pursue advanced topics on your own. Throughout the chapters, each component has been explicitly designed to engage and stimulate different parts of the brain so that you can retain and apply what you learn in the practical context with maximum impact. By completing the course from start to finish, you’ll walk away feeling capable of tackling any real-world Python development problem.
Table of Contents (16 chapters)
13
Chapter 13: The Evolution of Python – Discovering New Python Features

Creating custom iterators

The Pythonic secret that enables comprehensions to find all of the entries in a list, range, or other collection is an iterator. Supporting iterators in your classes opens them up for use in comprehensions, for…in loops, and anywhere that Python works with collections. Your collection must implement a method called __iter__(), which returns the iterator.

The iterator itself is also a Python object with a simple contract. It must provide a single method, __next__(). Each time __next__() is called, the iterator returns the next value in the collection. When the iterator reaches the end of the collection, __next__() raises StopIteration to signal that the iteration should terminate.

If you’ve used exceptions in other programming languages, you may be surprised by this use of an exception to signal a fairly commonplace situation. After all, plenty of loops reach an end, so it’s not exactly an exceptional circumstance. Python is not so...