Inheritance and Internals: OOP in Python (Summary)

Inheritance and Internals: Object-Oriented Programming in Python Christopher Trudeau 02:21

Now you know all about Python’s mechanisms for writing object-oriented code where the data and operations on that data are structured together. You’re an old pro at using the class keyword to create these structures. You can also base the definition of a class on other classes to create hierarchical structures and reuse your code. This mechanism is known as inheritance.

In this course, you’ve learned about:

Basic class inheritance
Multi-level inheritance, or classes that inherit from classes
Classes that inherit directly from more than one class, or multiple inheritance
Special methods that you can use when writing classes
Abstract base classes for classes that you don’t want to fully implement yet

To continue learning, you can watch the following video courses:

You can also check out the following written tutorials:

This course is the second in a three-part series. Part one is an introduction to class syntax, teaching you how to write a class and use its attributes and methods. Part three dives deeper into the philosophy behind writing good object-oriented code.

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Congratulations, you made it to the end of the course! What’s your #1 takeaway or favorite thing you learned? How are you going to put your newfound skills to use? Leave a comment in the discussion section and let us know.

00:00 In the previous lesson, I showed you abstract base classes and a duck typing approach to the sequence protocol. This lesson summarizes part two of the course.

00:11 You can build hierarchies of classes to better represent your real-world structures and to reuse your code. This is known as inheritance. A child class that extends a parent inherits its aspects.

00:25 A child isn’t stuck with those aspects. They can override them. If a child does override the parent, it can use super() to get at the parent’s methods, meaning they don’t have to rewrite them.

00:38 Class hierarchies can have as many levels as you like, and in fact, a class can also inherit from multiple parents. If you want to partially define a class to spec out an interface, the ABC module provides tools for doing that.

00:55 Everything in Python is an object (ka-ching!) and when you do things to that object, like adding, it’s done by invoking a dunder method. For example, the descriptor protocol uses dunder methods to make methods behave like attributes, and the sequence protocol uses dunder methods to make things list-like. The standard library takes full advantage of the class mechanisms in the language, implementing the data class shortcut to make it faster to write attributes and the Enum class to represent groups of constants.