As a teacher introducing Python to programmers experienced in other languages, I see another problem that this book tries to address: we only miss stuff we know about. Coming from another language, anyone may guess that Python supports regular expressions, and look that up in the docs. But if you’ve never seen tuple unpacking or descriptors before, you will probably not search for them, and you may end up not using those features just because they are specific to Python.

This book is not an A-to-Z exhaustive reference of Python. Its emphasis is on the language features that are either unique to Python or not found in many other popular languages. This is also mostly a book about the core language and some of its libraries. I will rarely talk about packages that are not in the standard library, even though the Python package index now lists more than 60,000 libraries, and many of them are incredibly useful.

Who This Book Is For

This book was written for practicing Python programmers who want to become proficient in Python 3. I tested the examples in Python 3.10—most of them also in Python 3.9 and 3.8. When an example requires Python 3.10, it should be clearly marked.

If you are not sure whether you know enough Python to follow along, review the topics of the official Python tutorial. Topics covered in the tutorial will not be explained here, except for some features that are new.

Who This Book Is Not For

If you are just learning Python, this book is going to be hard to follow. Not only that, if you read it too early in your Python journey, it may give you the impression that every Python script should leverage special methods and metaprogramming tricks. Premature abstraction is as bad as premature optimization.