Skip to ContentGo to accessibility pageKeyboard shortcuts menu
OpenStax Logo

Highlights from this chapter include:

  • Object-oriented programming involves grouping related fields and procedures into objects using data abstraction and encapsulation.
  • Classes define a type of object with attributes and methods.
  • Instances of a class type represent objects and are created using __init__().
  • Attributes may belong to the instance (unique for each instance) or the class (shared by all instances).
  • Instance methods have the first parameter self to access the specific instance.
  • Python uses magic methods to perform "under-the-hood" actions for users. Magic methods always start and end with double underscores.
  • Python allows overloading of existing operators for user-defined classes.
  • Classes can be imported from modules by name or can be renamed using aliases.

At this point, you should be able to write classes that have instance attributes, class attributes, and methods, and import classes from modules. You should also be able to overload operators when defining a class.

Construct Description
Class definition
class ClassName:
  """Docstring"""
__init__()
class ClassName:
  def __init__(self):
    # Initialize attributes
Attributes
class ClassName:
  class_attr_1 = [value]
  class_attr_2 = [value]

  def __init__(self):
    instance_attr_1 = [value]
    instance_attr_2 = [value]
    instance_attr_3 = [value]
Methods (instance)
class ClassName:

  def __init__(self):
    instance_attr_1 = [value]
    instance_attr_2 = [value]
    instance_attr_3 = [value]

  def method_1(self, val1, val2):
    # Access/change attributes

  def method_2(self):
    # Access/change attributes
Instances
instance_1 = ClassName()
instance_1.instance_attr_1 = [new value]
instance_2 = ClassName()
instance_2.method_2()
Overloaded multiplication operator
class ClassName:
  # Other methods

  def __mul__(self, other):
    return ClassName(self.instance_attr_3 * other.instance_attr_3)
Import class from module with alias
from class_module import ClassName as ClassAlias
Table 11.4 Chapter 11 reference.
Citation/Attribution

This book may not be used in the training of large language models or otherwise be ingested into large language models or generative AI offerings without OpenStax's permission.

Want to cite, share, or modify this book? This book uses the Creative Commons Attribution License and you must attribute OpenStax.

Attribution information
  • If you are redistributing all or part of this book in a print format, then you must include on every physical page the following attribution:
    Access for free at https://openstax.org/books/introduction-python-programming/pages/1-introduction
  • If you are redistributing all or part of this book in a digital format, then you must include on every digital page view the following attribution:
    Access for free at https://openstax.org/books/introduction-python-programming/pages/1-introduction
Citation information

© Jul 30, 2024 OpenStax. Textbook content produced by OpenStax is licensed under a Creative Commons Attribution License . The OpenStax name, OpenStax logo, OpenStax book covers, OpenStax CNX name, and OpenStax CNX logo are not subject to the Creative Commons license and may not be reproduced without the prior and express written consent of Rice University.

This book utilizes the OpenStax Python Code Runner. The code runner is developed by Wiley and is All Rights Reserved.