Topic 1: Introduction to OOP Concepts

1. What is Object-Oriented Programming (OOP)?

Object-Oriented Programming (OOP) is a programming paradigm centered around objects and data rather than actions and logic. Objects often represent real-world entities, and their methods define interactions between these entities.

2. Four Pillars of OOP

The main concepts, or pillars, of OOP are:

a. Encapsulation

Encapsulation is the bundling of data (attributes) and methods (functions) that operate on the data into a single unit or class. It also restricts direct access to some of the object’s components, which is a means of preventing unintended interference and misuse of the data.


class Car: def __init__(self, brand, model): self._brand = brand # _ before attribute name suggests it's protected (convention) self._model = model def get_brand(self): return self._brand def set_brand(self, brand): self._brand = brand

Here, _brand and _model are encapsulated within the Car class.

b. Abstraction

Abstraction refers to the idea of hiding complex implementation details and showing only the essential features of an object, thus simplifying how you interface with the object.

Example: In the above Car class, a user doesn’t need to know how the brand is stored or retrieved, only that they can use get_brand() and set_brand() methods.

c. Inheritance

Inheritance allows a class (child or subclass) to inherit properties and methods from another class (parent or superclass). This promotes code reusability and establishes a relationship between the parent and child classes.


class ElectricCar(Car): # ElectricCar inherits from Car def __init__(self, brand, model, battery_size): super().__init__(brand, model) self.battery_size = battery_size

In this case, ElectricCar inherits the properties and methods of Car and introduces a new attribute, battery_size.

d. Polymorphism

Polymorphism refers to the ability of different objects to be treated as instances of the same class through inheritance. In essence, it allows objects to use methods with the same name but possibly with different implementations.


class Pet: def sound(self): pass class Dog(Pet): def sound(self): return "Woof!" class Cat(Pet): def sound(self): return "Meow!" def animal_sound(pet): print(pet.sound()) # Using Polymorphism dog = Dog() cat = Cat() animal_sound(dog) # Outputs: Woof! animal_sound(cat) # Outputs: Meow!

In this example, both Dog and Cat have a method named sound, but the implementations are different. Yet, the animal_sound function can operate on any Pet object.

3. Advantages of OOP

  • Modularity: OOP allows for a modular approach where classes can be developed and maintained separately.

  • Reusability: Through inheritance, classes can reuse the properties and behaviors of existing classes.

  • Flexibility: Through polymorphism, OOP facilitates flexibility in invoking methods, leading to more dynamic and versatile code.

  • Maintainability: Encapsulation and abstraction ensure that changes in one part of the code have minimal impact on other parts, making maintenance easier.

4. Conclusion

Understanding the concepts of OOP is fundamental to building efficient, modular, and maintainable software. As you delve further into Python and its capabilities, leveraging the principles of OOP will greatly aid in structuring your code more effectively and intuitively.