Lesson: OOP (Object-Oriented Programming) in Python by prompt AI teaching assistant

 

Lesson: OOP (Object-Oriented Programming) in Python

[introduction]

Welcome back! Today we’ll explore Object-Oriented Programming (OOP), a powerful way to structure and organize Python programs. By the end of this lesson, you’ll understand classes, objects, attributes, methods, and why OOP is so useful.

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[concept_explanation]

OOP is a programming style built around objects.
An object is something that has:

• Attributes (data → variables inside the object)

• Methods (behavior → functions inside the object)

In Python, OOP centers around classes, which are blueprints for creating objects.

Key concepts you must know:

1. Class — a blueprint or template

2. Object / Instance — a concrete version of a class

3. Attributes — variables that belong to an object

4. Methods — functions that belong to an object

5. __init__ method — the constructor, runs when you create an object

6. self keyword — refers to the current object, required in methods

OOP helps with code organization, reusability, readability, and modeling real-world problems.

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[python_examples]

1. Creating a basic class

class Person:
    def __init__(self, name, age):   # constructor
        self.name = name
        self.age = age

    def introduce(self):             # method
        print(f"My name is {self.name} and I am {self.age} years old.")

# Creating an object
p = Person("Alex", 18)
p.introduce()

2. Adding another method

class Dog:
    def __init__(self, breed):
        self.breed = breed

    def bark(self):
        print("Woof!")

my_dog = Dog("Labrador")
my_dog.bark()

3. Inheritance

class Animal:
    def speak(self):
        print("Some sound")

class Cat(Animal):        # Cat inherits from Animal
    def speak(self):
        print("Meow")

c = Cat()
c.speak()

4. Using super()

class Vehicle:
    def __init__(self, brand):
        self.brand = brand

class Car(Vehicle):
    def __init__(self, brand, model):
        super().__init__(brand)
        self.model = model

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[analogy]

Think of a class like a cookie cutter and an object like a cookie.
The cookie cutter (class) defines the shape, and each cookie (object) is created using that shape.
Different cookies may have different decorations (values), but they all follow the same design.

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[practice_task]

Try creating your own class:

1. Make a class called Student.

2. Give it attributes: name, grade.

3. Add a method called display_info() that prints them nicely.

4. Create at least two Student objects and call the method on each.

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[quiz]

1. What keyword is used to define a class in Python?

2. What is the purpose of the __init__ method?

3. What does self represent?

4. What will this code print?

class A:
    def show(self):
        print("Hello")

obj = A()
obj.show()

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[common_mistakes]

• Forgetting to include self in method definitions

• Misunderstanding that attributes must be accessed with self.attribute_name

• Confusing classes and objects

• Forgetting to use () when creating an object

• Overcomplicating classes when simple functions would do

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[extra_notes]

• Python supports multiple inheritance.

• You can create private-like attributes using a leading underscore (_value).

• Special (magic) methods like __str__ and __len__ allow custom object behavior.

• OOP is powerful but should be used when it makes structure clearer—not everywhere.

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[encouragement]

Great work! OOP is an advanced topic, and understanding it puts you on a whole new level as a Python programmer. You're learning fast and doing excellent.