Book Image

Expert Python Programming - Fourth Edition

By : Michał Jaworski, Tarek Ziadé
Book Image

Expert Python Programming - Fourth Edition

By: Michał Jaworski, Tarek Ziadé

Overview of this book

This new edition of Expert Python Programming provides you with a thorough understanding of the process of building and maintaining Python apps. Complete with best practices, useful tools, and standards implemented by professional Python developers, this fourth edition has been extensively updated. Throughout this book, you’ll get acquainted with the latest Python improvements, syntax elements, and interesting tools to boost your development efficiency. The initial few chapters will allow experienced programmers coming from different languages to transition to the Python ecosystem. You will explore common software design patterns and various programming methodologies, such as event-driven programming, concurrency, and metaprogramming. You will also go through complex code examples and try to solve meaningful problems by bridging Python with C and C++, writing extensions that benefit from the strengths of multiple languages. Finally, you will understand the complete lifetime of any application after it goes live, including packaging and testing automation. By the end of this book, you will have gained actionable Python programming insights that will help you effectively solve challenging problems.
Table of Contents (16 chapters)
14
Other Books You May Enjoy
15
Index

Metaclasses

A metaclass is a Python feature that is considered by many as one of the most difficult things to understand in the language and is thus avoided by a great number of developers. In reality, it is not as complicated as it sounds once you understand a few basic concepts. As a reward, knowing how to use metaclasses grants you the ability to do things that are not possible without them.

A metaclass is a type (class) that defines other types (classes). The most important thing to know in order to understand how they work is that classes (so, types that define object structure and behavior) are objects too. So, if they are objects, then they have an associated class. The basic type of every class definition is simply the built-in type class (see Figure 8.1).

Figure 8.1: How classes are typed

In Python, it is possible to substitute the metaclass for a class object with your own type. Usually, the new metaclass is still the subclass of the type metaclass (refer...