Book Image

Python 3 Object-Oriented Programming - Third Edition

By : Dusty Phillips
Book Image

Python 3 Object-Oriented Programming - Third Edition

By: Dusty Phillips

Overview of this book

Object-oriented programming (OOP) is a popular design paradigm in which data and behaviors are encapsulated in such a way that they can be manipulated together. This third edition of Python 3 Object-Oriented Programming fully explains classes, data encapsulation, and exceptions with an emphasis on when you can use each principle to develop well-designed software. Starting with a detailed analysis of object-oriented programming, you will use the Python programming language to clearly grasp key concepts from the object-oriented paradigm. You will learn how to create maintainable applications by studying higher level design patterns. The book will show you the complexities of string and file manipulation, and how Python distinguishes between binary and textual data. Not one, but two very powerful automated testing systems, unittest and pytest, will be introduced in this book. You'll get a comprehensive introduction to Python's concurrent programming ecosystem. By the end of the book, you will have thoroughly learned object-oriented principles using Python syntax and be able to create robust and reliable programs confidently.
Table of Contents (15 chapters)

Empty objects

Let's start with the most basic Python built-in, one that we've seen many times already, the one that we've extended in every class we have created: the object. Technically, we can instantiate an object without writing a subclass, as follows:

    >>> o = object()
    >>> o.x = 5
    Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
    AttributeError: 'object' object has no attribute 'x'  

Unfortunately, as you can see, it's not possible to set any attributes on an object that was instantiated directly. This isn't because the Python developers wanted to force us to write our own classes, or anything so sinister. They did this to save memory; a lot of memory. When Python allows an object to have arbitrary attributes, it takes a certain amount of system memory...