Itse1359-1410-overview of python classes

Table of contents

• Preface
  • What you have learned
  • What you will learn
  • Viewing tip
    • Figures
    • Listings
• Preview
• General background information
  • A class definition is a blueprint for objects
  • Three important OOP concepts
    • What is an Object-Oriented Program?
    • What is encapsulation?
• Discussion and sample code
  • A real-world analogy -- a car radio
    • The ability to store data
    • The user interface
    • Modifying the stored data
    • Responding to a message
    • Jargon
    • Where do objects come from?
  • Program code
    • Manufacture a three-button radio
    • Scan for available stations
    • Program the buttons on radio01
    • Play the three programmed stations
    • Manufacture another 3-button radio
    • The class named Radio
    • A class variable named stations
    • The __init__ method
    • The word self
    • Three more methods
• Visualizing a class definition
• Run the program
• Complete program listing
• Miscellaneous

Preface

This module is one in a collection of modules on Python designed for teaching ITSE 1359 Introduction to Scripting Languages: Python at Austin Community College in Austin, TX.

What you have learned

Previous modules have helped you to learn the basics of programming in Python such as syntax, numbers, variables, strings, scripts, lists, tuples,dictionaries, operators, etc.

Previous modules have also helped you to learn about control flow including if statements, while loops, for loops, functions, function arguments, etc.

What you will learn

The time has come for you to learn about classes and objects . This is the first of several modules that explain classes and objects in Python.

This module provides an overview. Future modules will dig deeper into the details of using classes and objects.

Viewing tip

I recommend that you open another copy of this module in a separate browser window and use the following links to easily find and view the Figuresand the Listings while you are reading about them.

(Note to blind and visually impaired students: Most of the Figures and all of the Listings inthis module are presented in plain text format and should be accessible using an audio screen reader or a braille display. Note however that the requiredindentation may not be properly represented by an audio screen reader.)

Figures

• Figure 1 . Output from the code in Listing 2.
• Figure 2 . Output from the code in Listing 3.
• Figure 3 . Output from the code in Listing 4.
• Figure 4 . Output from the code in Listing 5.
• Figure 5 . Visualizing a class definition.
• Figure 6 . Output from the program in Listing 9.

Listings

• Listing 1 . Manufacture a three-button radio.
• Listing 2 . Scan for available stations.
• Listing 3 . Program the buttons on radio01.
• Listing 4 . Play the three programmed stations.
• Listing 5 . Manufacture another 3-button radio.
• Listing 6 . Beginning of the class named Radio.
• Listing 7 . The __init__ method.
• Listing 8 . Three more methods.
• Listing 9 . Complete program listing.

Preview

This module will concentrate primarily on a discussion of the Python class and objects created using Python classes.