Object-Oriented Programming in Python

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Questions and Answers

What is the purpose of a class in object-oriented programming?

To perform actions without storing data

To define attributes and methods for instances (correct)

To represent only the methods associated with an instance

To create multiple unique copies of itself

Which of the following correctly describes attributes in a class?

Attributes are functions that perform actions for a class

Attributes are properties that store data related to the class (correct)

Attributes can only be listed using the dir() function

Attributes are synonymous with instances of the class

What is a constructor in a class?

A special method that initializes attributes for new instances (correct)

A keyword to define an empty class

A method to list attributes of a class

A function that deletes instances of the class

What does the pass keyword signify in class definition?

That some parts of the class remain intentionally undefined Signup and view all the answers

How can you access an attribute of an instance in Python?

instance.attribute Signup and view all the answers

Which naming convention is typically used for classes in Python?

CapWords Signup and view all the answers

What is the dir() function used for in the context of a class?

To list all the attributes of a class Signup and view all the answers

How does a method differ from an attribute in a class context?

Methods perform actions, whereas attributes store data Signup and view all the answers

What is the primary purpose of the 'self' keyword in method calls?

To refer to the calling object Signup and view all the answers

Which of the following best describes encapsulation in OOP?

Hiding the internal details of a class Signup and view all the answers

What does polymorphism in OOP allow for?

Sending a message to any object with varied responses Signup and view all the answers

Which principle of OOP allows for the creation of new objects based on existing ones?

Inheritance Signup and view all the answers

In the context of OOP, what is meant by modularity?

Creating objects that can stand alone for reuse Signup and view all the answers

What is a key characteristic of all objects in Python?

They are strictly defined by their classes Signup and view all the answers

How does software engineering benefit from object-oriented programming?

By simplifying code structure without altering functionality Signup and view all the answers

Study Notes

Binding `self`

When a method is called on an object, self automatically refers to that object.
self is used to access and manipulate the object's attributes.
Any attribute reference within a method must use self.
Methods can work with any object of a class by using self.

Object-Oriented Programming (OOP)

OOP structures code around "objects" that have data and behavior (methods).
OOP makes code easier to model real-world systems.
A program in OOP is a collection of interacting objects.
Everything in Python is an object.
OOP is based on encapsulation, modularity, inheritance, and polymorphism.

Encapsulation

Encapsulation hides internal details of an object to improve readability and maintainability.

Modularity

Modularity means objects can be used independently in different parts of a program.

Inheritance

Inheritance creates new objects by inheriting attributes/methods from other objects (parent to child).

Polymorphism

Polymorphism lets objects respond appropriately to the same message (method call) in different ways.

Software Engineering (SE)

SE involves managing code to ensure long-term usability.
SE includes modifying code without affecting functionality.
SE aims for simpler and understandable code.

Classes

Classes are templates for creating objects (instances).
Defining a class structures data and methods for instances.
Classes enable reusability and organized code.
Example of a class: A Student class has attributes/methods like name, age, study, take_exam.

Class vs. Instance

Class: Defines structure and behavior for instances.
Instance: A specific object of a class with unique data.
Classes and instances are objects themselves.
Instances are structured according to the class that creates them.

Why Classes

Classes create reusable, complex data types for programs.
A class consists of attributes (data) and methods (actions).

Anatomy of a Class

Class Name: Use CapWords (e.g., MyClass).
Attributes: Stored data elements for each instance.
Methods: Functions within a class.
Constructor (__init__): Initializes attributes when an instance is created.

`dir()` Function

dir() lists all attributes (variables and methods) of a class.

`pass` Keyword

pass is used to indicate an empty block; it does nothing.
Used when a particular block is undefined. This makes the class only contain the objects Python defines automatically.

Constructor (`init`)

The constructor (__init__) is a special method within a class.
It initializes an object’s attributes when the object is created.

Dot Reference

Dot reference (e.g., object.attribute) accesses an attribute of an object.
The attribute can be a variable or a method.
Methods are distinguished from variables by the parentheses after them (like a function call).

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Description

This quiz covers fundamental concepts of Object-Oriented Programming (OOP) in Python, including self, encapsulation, modularity, inheritance, and polymorphism. Test your understanding of how these principles interact to model real-world scenarios effectively.