Python Classes & Objects Tutorial - __init__, self, inheritance, super() Explained

Python Classes & Objects Tutorial - __init__, self, inheritance, super() Explained

This tutorial covers the fundamentals of Python classes and objects, showing how to define classes with the class keyword and initialize them using the __init__ method. It also explains instance attributes via self, creating and modifying objects, and introduces inheritance and method overriding using super().

Code

# Define a basic class with attributes and methods
class Dog:
  def __init__(self, name, breed, age):
    # Initialize instance attributes
    self.name = name
    self.breed = breed
    self.age = age

  def bark(self):
    # Instance method using self
    return f"{self.name} says Woof!"

# Create an instance of Dog
rex = Dog("Rex", "German Shepherd", 5)
print(rex.bark())  # Output: Rex says Woof!

# Define a base class
class Animal:
  def __init__(self, name, age):
    self.name = name
    self.age = age

  def speak(self):
    return f"{self.name} makes a sound."

# Inherit from Animal and extend functionality
class Cat(Animal):
  def __init__(self, name, age, color):
    # Call parent constructor to initialize name and age
    super().__init__(name, age)
    self.color = color

  # Override speak method
  def speak(self):
    return f"{self.name} says Meow!"

# Create a Cat instance
whiskers = Cat("Whiskers", 3, "Tabby")
print(whiskers.speak())  # Output: Whiskers says Meow!

Key Points

• Use the class keyword and __init__ method to define and initialize objects.
• self refers to the instance and is used to access attributes and methods.
• Inheritance allows a class to reuse and extend functionality from a parent class.
• super().__init__() calls the parent class constructor to set up inherited attributes.
• Method overriding lets subclasses customize or replace parent class behavior.