Book Image

Mastering Python 2E - Second Edition

By : Rick van Hattem
5 (1)
Book Image

Mastering Python 2E - Second Edition

5 (1)
By: Rick van Hattem

Overview of this book

Even if you find writing Python code easy, writing code that is efficient, maintainable, and reusable is not so straightforward. Many of Python’s capabilities are underutilized even by more experienced programmers. Mastering Python, Second Edition, is an authoritative guide to understanding advanced Python programming so you can write the highest quality code. This new edition has been extensively revised and updated with exercises, four new chapters and updates up to Python 3.10. Revisit important basics, including Pythonic style and syntax and functional programming. Avoid common mistakes made by programmers of all experience levels. Make smart decisions about the best testing and debugging tools to use, optimize your code’s performance across multiple machines and Python versions, and deploy often-forgotten Python features to your advantage. Get fully up to speed with asyncio and stretch the language even further by accessing C functions with simple Python calls. Finally, turn your new-and-improved code into packages and share them with the wider Python community. If you are a Python programmer wanting to improve your code quality and readability, this Python book will make you confident in writing high-quality scripts and taking on bigger challenges
Table of Contents (21 chapters)
19
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20
Index

Dynamically creating classes

Metaclasses are the factories that create new classes in Python. In fact, even though you may not be aware of it, Python will always execute the type metaclass whenever you create a class.

A few common examples where metaclasses are used internally are abc (abstract base classes), dataclasses, and the Django framework, which heavily relies on metaclasses for the Model class.

When creating classes in a procedural way, the type metaclass is used as a function that takes three arguments: name, bases, and dict.name will become the __name__ attribute, bases is the list of inherited base classes and will be stored in __bases__, and dict is the namespace dictionary that contains all variables and will be stored in __dict__.

It should be noted that the type() function has another use as well. Given the arguments documented above, it will create a class with those specifications. Given a single argument with the instance of a class (for example, type...