Learning Python, 3rd Edition

Chapter 26. Advanced Class Topics

This chapter concludes Part VI and our look at OOP in Python by presenting a few more advanced class-related topics: we will survey subclassing built-in types, pseudoprivate attributes, new-style classes, static methods, function decorators, and more.

As we’ve seen, Python’s OOP model is, at its core, very simple, and some of the topics presented in this chapter are so advanced and optional that you may not encounter them very often in your Python applications-programming career. In the interest of completeness, though, we’ll round out our discussion of classes with a brief look at these advanced tools for advanced OOP work.

As usual, because this is the last chapter in this part of the book, it ends with a section on class-related gotchas, and the set of lab exercises for this part. I encourage you to work through the exercises to help cement the ideas we’ve studied here. I also suggest working on or studying larger OOP Python projects as a supplement to this book. As with much in computing, the benefits of OOP tend to become more apparent with practice.

Extending Built-in Types

Besides implementing new kinds of objects, classes are sometimes used to extend the functionality of Python’s built-in types to support more exotic data structures. For instance, to add queue insert and delete methods to lists, you can code classes that wrap (embed) a list object, and export insert and delete methods that process the list specially, like the delegation technique ...