Book Image

Python 3 Object Oriented Programming

By : Dusty Phillips
Book Image

Python 3 Object Oriented Programming

By: Dusty Phillips

Overview of this book

Object Oriented Programming is a very important aspect of modern programming languages. The basic principles of Object Oriented Programming are relatively easy to learn. Putting them together into working designs can be challenging.This book makes programming more of a pleasure than a chore using powerful Python 3 object-oriented features of Python 3. It clearly demonstrates the core OOP principles and how to correctly implement OOP in Python. Object Oriented Programming ranks high in importance among the many models Python supports. Yet, many programmers never bother learning the powerful features that make this language object oriented.The book teaches when and how OOP should be correctly applied. It emphasizes not only the simple syntax of OOP in Python, but also how to combine these objects into well-designed software.This book will introduce you to the terminology of the object-oriented paradigm, focusing on object-oriented design with step-by-step examples. It will take you from simple inheritance, one of the most useful tools in the object-oriented programmer's toolbox, all the way through to cooperative inheritance, one of the most complicated. You will be able to raise, handle, define, and manipulate exceptions.You will be able to integrate the object-oriented and the not-so-object-oriented aspects of Python. You will also be able to create maintainable applications by studying higher level design patterns. You'll learn 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 will be introduced to you. You'll understand the joy of unit testing and just how easy they are to create. You'll even study higher level libraries such as database connectors and GUI toolkits and how they apply object-oriented principles.
Table of Contents (18 chapters)
Python 3 Object Oriented Programming
Credits
About the Author
About the Reviewers
Preface
Index

Polymorphism


We introduced polymorphism in Chapter 1. It is a fancy name describing a simple concept; different behaviors happen depending on which subclass is being used, without having to explicitly know what the subclass actually is. As an example, imagine a program that plays audio files. A media player might need to load an AudioFile object and then play it. We'd put a play() method on the object, which is responsible for decompressing or extracting the audio and routing it to the sound card and speakers. The act of playing an AudioFile could feasibly be as simple as:

audio_file.play()

However the process of decompressing and extracting an audio file is very different for different types of files. The .wav files are stored uncompressed, while .mp3, .wma, and .ogg files all have very different compression algorithms.

We can use inheritance with polymorphism to simplify the design. Each type of file can be represented by a different subclass of AudioFile, for example, WavFile, MP3File. Each...