Class and Objects in Python Review

Perfect timing to review this before Django 👍
Django is very class-heavy, so getting this clear will make everything feel easier.

What is a Class in Python?

A class is a blueprint (template) to create objects.

Think:

Class → Design of a house 🏠
Object → Actual house built from that design

What is an Object?

An object is an instance of a class.
It holds real data and can use the class’s methods.

Basic Example (Very Important)

class Student:
    def __init__(self, name, roll):
        self.name = name
        self.roll = roll

    def info(self):
        print(self.name, self.roll)

Creating Objects

s1 = Student("Aarav", 1)
s2 = Student("Sita", 2)

s1.info()
s2.info()

Output

Aarav 1
Sita 2

Key Terms You MUST Know

1. `init` (Constructor)

Runs automatically when object is created
Used to initialize data

def __init__(self):
    pass

2. `self`

Refers to current object
Without self, Django will break 😄

❌ Wrong:

name = name

✅ Correct:

self.name = name

Class Variables vs Instance Variables

class College:
    college_name = "ABC College"   # class variable

    def __init__(self, student):
        self.student = student     # instance variable

c1 = College("Ram")
c2 = College("Shyam")

print(c1.college_name)
print(c2.college_name)

Methods in Class

Instance Method

def show(self):
    print(self.name)

Class Method

@classmethod
def college(cls):
    print("ABC College")

Static Method

@staticmethod
def hello():
    print("Hello")

Inheritance (VERY IMPORTANT FOR DJANGO)

class User:
    def login(self):
        print("User logged in")

class Admin(User):
    def delete(self):
        print("Deleted")

a = Admin()
a.login()
a.delete()

➡ Django uses inheritance everywhere (models.Model, views.View)

Encapsulation (Basics)

class Bank:
    def __init__(self, balance):
        self.__balance = balance  # private

    def get_balance(self):
        return self.__balance

Why Classes Matter in Django (BIG PICTURE)

Django Part	Class Usage
Models	`class Product(models.Model)`
Views	`class ProductView(View)`
Forms	`class ProductForm(forms.ModelForm)`
Admin	`class ProductAdmin(admin.ModelAdmin)`

Django-Style Preview Example

class Product:
    def __init__(self, name, price):
        self.name = name
        self.price = price

    def discounted_price(self):
        return self.price - 10

➡ This is exactly how Django Models think, just with extra magic.

Quick Practice Tasks (Before Django)

Task 1

Create a class Teacher with:

name
subject
method details()

Task 2

Create a class Car:

brand (class variable)
model
method show()

Task 3 (Django mindset)

Create:

class User:
    username
    email
    method: display()

Class and Objects in Python Review

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What is a Class in Python?

What is an Object?

Basic Example (Very Important)

Creating Objects

Output

Key Terms You MUST Know

1. `init` (Constructor)

2. `self`

Class Variables vs Instance Variables

Methods in Class

Instance Method

Class Method

Static Method

Inheritance (VERY IMPORTANT FOR DJANGO)

Encapsulation (Basics)

Why Classes Matter in Django (BIG PICTURE)

Django-Style Preview Example

Quick Practice Tasks (Before Django)

Task 1

Task 2

Task 3 (Django mindset)

Command Palette

Comments

More from this blog

What is a Class in Python?

What is an Object?

Basic Example (Very Important)

Creating Objects

Output

Key Terms You MUST Know

1. __init__ (Constructor)

2. self

Class Variables vs Instance Variables

Methods in Class

Instance Method

Class Method

Static Method

Inheritance (VERY IMPORTANT FOR DJANGO)

Encapsulation (Basics)

Why Classes Matter in Django (BIG PICTURE)

Django-Style Preview Example

Quick Practice Tasks (Before Django)

Task 1

Task 2

Task 3 (Django mindset)

1. `init` (Constructor)

2. `self`