Introduction to OOP in Python

Introduction to Object-Oriented Programming (OOP)

• OOP is a programming paradigm that utilizes objects and classes.
• Classes serve as blueprints, defining the structure and behavior of objects.
• Object examples in Python: integers, strings, lists, tuples, and dictionaries.
• Python treats everything that can be assigned to a variable as an object except reserved keywords.

Key Concepts of OOP

• Core components of OOP include:
  • Objects
  • Classes
  • Inheritance
  • Polymorphism
  • Encapsulation
  • Composition
• Classes are fundamental to OOP, serving as templates for creating object instances.

Class and Instance Relationship

• A class acts as a blueprint, while instances are physical realizations based on that blueprint.
• Multiple instances can differ in state but share the same methods.
• For example, two lists created from the List class can have distinct contents but the same methods.

Advantages of Using Classes

• Classes allow developers to define custom object types, enhancing abstraction.
• This abstraction helps in organizing complex programs like libraries or applications (e.g., NumPy, requests).

Game Programming Example

• Classes can encapsulate player information and behaviors, simplifying game logic and organization of related functions.

Class Syntax and Structure

• A basic class is defined using specific syntax, with attributes (variables) and methods (functions).
• Class methods can be called from instances or directly from the class.
• The first parameter of class methods is typically named self, representing the instance.

Initialization with __init__

• The __init__ method is the constructor of a class, automatically invoked during instantiation.
• __init__ can accept arguments and assign them to instance attributes using the self variable.
• Instance attributes are specific to each instance, maintaining separate states.

Class Attributes versus Instance Attributes

• Class attributes are shared across all instances of a class and persist as constants.
• Updating a class attribute affects all instances, but instance attributes remain independent.

Class Methods

• Class methods are functions that belong to a class, performing actions based on the class’s attributes.
• They can be called using either the class or an instance, with the same functional outcome.
• Self is consistently the first parameter, linking methods to their class.

Special Functionality with __dunder__ Methods

• __dunder__ (double underscore) methods are special functions that provide additional functionality, allowing for operator overloading and other custom behavior.