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Classes and Objects in Python

Master the foundation of Object-Oriented Programming — learn how to define classes, create objects, use attributes and methods, and understand how Python models real-world entities as code.

🧠 Real-World Analogy — Blueprint aur Building

Think of an architect's blueprint — it's a design that specifies what the building will look like: how many floors, how many rooms, where the doors are. When a contractor builds an actual building from that blueprint — that's an object. From one blueprint, you can build thousands of different buildings — each with its own location, color, and address.

In Python:

Class = Blueprint (design / template)
Object = Actual instance built from that blueprint

📐 ASCII Class Diagram

text example

+---------------------------+
|         Car               |   ← Class Name
+---------------------------+
| - make: str               |   ← Attributes (data)
| - model: str              |
| - year: int               |
| - speed: float            |
+---------------------------+
| + start()                 |   ← Methods (behavior)
| + accelerate(amount)      |
| + brake()                 |
| + get_info() -> str       |
+---------------------------+

🚗 Example 1 — Defining a Class and Creating Objects

Example

class Car: """A simple Car class.""" # Class variable (shared by ALL instances) total_cars = 0 def __init__(self, make, model, year): # Instance variables (unique to each object) self.make = make self.model = model self.year = year self.speed = 0 Car.total_cars += 1 # increment shared counter def start(self): print(f"{self.make} {self.model} engine started! 🚗") def accelerate(self, amount): self.speed += amount print(f"Speed increased to {self.speed} km/h") def brake(self): self.speed = max(0, self.speed - 20) print(f"Braking... speed is now {self.speed} km/h") def get_info(self): return f"{self.year} {self.make} {self.model}" # ── Creating objects ────────────────────────────────────── car1 = Car("Toyota", "Camry", 2022) car2 = Car("Honda", "Civic", 2023) car3 = Car("Tesla", "Model 3", 2024) # ── Calling methods ─────────────────────────────────────── car1.start() car1.accelerate(60) car1.accelerate(40) car1.brake() print(car2.get_info()) print(f"Total cars created: {Car.total_cars}")

Output:

Example

Toyota Camry engine started! 🚗 Speed increased to 60 km/h Speed increased to 100 km/h Braking... speed is now 80 km/h 2023 Honda Civic Total cars created: 3

🔍 Understanding `self`

self means "this object itself". When you call car1.start(), Python automatically passes car1 as self.

python example

# These two calls are IDENTICAL:
car1.start()          # ← short form (Python sugar)
Car.start(car1)       # ← explicit form (shows what really happens)

self is NOT a keyword — it is a convention. You could name it anything, but always use self.

🏗️ Class Variables vs Instance Variables

python example

class Student:
    school_name = "WoHoTech Academy"   # ← class variable (shared)

    def __init__(self, name, grade):
        self.name = name               # ← instance variable (unique)
        self.grade = grade

    def introduce(self):
        print(f"Hi, I'm {self.name}, grade {self.grade} at {Student.school_name}")


s1 = Student("Arjun", 10)
s2 = Student("Priya", 11)

s1.introduce()
s2.introduce()

# Changing class variable affects ALL instances
Student.school_name = "WoHoTech Global Academy"
s1.introduce()   # updated!
s2.introduce()   # updated!

# Changing instance variable affects ONLY that instance
s1.name = "Arjun Kumar"
print(s1.name)   # Arjun Kumar
print(s2.name)   # Priya  (unchanged)

Output:

Example

Hi, I'm Arjun, grade 10 at WoHoTech Academy Hi, I'm Priya, grade 11 at WoHoTech Academy Hi, I'm Arjun, grade 10 at WoHoTech Global Academy Hi, I'm Priya, grade 11 at WoHoTech Global Academy Arjun Kumar Priya

🏦 Example 2 — Bank Account

python example

class BankAccount:
    bank_name = "WoHo National Bank"
    interest_rate = 0.04   # 4% annual

    def __init__(self, owner, balance=0):
        self.owner = owner
        self._balance = balance       # convention: _ means "protected"
        self.transactions = []

    def deposit(self, amount):
        if amount <= 0:
            print("❌ Deposit amount must be positive.")
            return
        self._balance += amount
        self.transactions.append(f"+₹{amount}")
        print(f"✅ Deposited ₹{amount}. New balance: ₹{self._balance}")

    def withdraw(self, amount):
        if amount > self._balance:
            print(f"❌ Insufficient funds. Balance: ₹{self._balance}")
            return
        self._balance -= amount
        self.transactions.append(f"-₹{amount}")
        print(f"✅ Withdrew ₹{amount}. New balance: ₹{self._balance}")

    def get_balance(self):
        return self._balance

    def add_interest(self):
        interest = self._balance * BankAccount.interest_rate
        self._balance += interest
        print(f"💰 Interest added: ₹{interest:.2f}. New balance: ₹{self._balance:.2f}")

    def statement(self):
        print(f"\n{'='*40}")
        print(f"  {BankAccount.bank_name}")
        print(f"  Account holder: {self.owner}")
        print(f"  Balance: ₹{self._balance}")
        print(f"  Transactions: {', '.join(self.transactions)}")
        print(f"{'='*40}\n")


acc1 = BankAccount("Rahul Sharma", 10000)
acc2 = BankAccount("Sneha Gupta", 5000)

acc1.deposit(2000)
acc1.withdraw(500)
acc1.add_interest()
acc1.statement()

acc2.withdraw(6000)   # should fail
acc2.deposit(1000)
acc2.statement()

Output:

✅ Deposited ₹2000. New balance	₹12000
✅ Withdrew ₹500. New balance	₹11500
💰 Interest added	₹460.00. New balance: ₹11960.00
Account holder	Rahul Sharma
Balance	₹11960.0
Transactions	+₹2000, -₹500
❌ Insufficient funds. Balance	₹5000
✅ Deposited ₹1000. New balance	₹6000
Account holder	Sneha Gupta
Balance	₹6000
Transactions	+₹1000

📦 Example 3 — Product Inventory

Example

class Product: """Represents a product in an inventory system.""" _id_counter = 1000 def __init__(self, name, price, quantity): self.product_id = f"PRD-{Product._id_counter}" Product._id_counter += 1 self.name = name self.price = price self.quantity = quantity def total_value(self): return self.price * self.quantity def restock(self, units): self.quantity += units print(f"Restocked {units} units of '{self.name}'. Total: {self.quantity}") def sell(self, units): if units > self.quantity: print(f"❌ Only {self.quantity} units available.") return 0 self.quantity -= units revenue = units * self.price print(f"✅ Sold {units} x '{self.name}' = ₹{revenue}") return revenue def display(self): print(f"[{self.product_id}] {self.name:20s} | Price: ₹{self.price:>8.2f} | Qty: {self.quantity:>5}") # Create inventory items = [ Product("Python Book", 599.0, 50), Product("USB-C Cable", 299.0, 120), Product("Laptop Stand", 1499.0, 30), Product("Mechanical Keyboard", 3499.0, 15), ] print("── Inventory ──────────────────────────────") for item in items: item.display() items[0].sell(10) items[1].sell(200) # should fail items[2].restock(20) print("\n── Updated Inventory ──────────────────────") for item in items: item.display() total = sum(i.total_value() for i in items) print(f"\nTotal inventory value: ₹{total:,.2f}")

Output:

[PRD-1000] Python Book \| Price	₹ 599.00 \| Qty: 50
[PRD-1001] USB-C Cable \| Price	₹ 299.00 \| Qty: 120
[PRD-1002] Laptop Stand \| Price	₹ 1499.00 \| Qty: 30
[PRD-1003] Mechanical Keyboard \| Price	₹ 3499.00 \| Qty: 15
Restocked 20 units of 'Laptop Stand'. Total	50
[PRD-1000] Python Book \| Price	₹ 599.00 \| Qty: 40
[PRD-1001] USB-C Cable \| Price	₹ 299.00 \| Qty: 120
[PRD-1002] Laptop Stand \| Price	₹ 1499.00 \| Qty: 50
[PRD-1003] Mechanical Keyboard \| Price	₹ 3499.00 \| Qty: 15
Total inventory value	₹1,37,745.00

🔬 Object Identity, Equality and Type

python example

car1 = Car("Toyota", "Camry", 2022)
car2 = Car("Toyota", "Camry", 2022)
car3 = car1   # same reference!

# Identity (same object in memory?)
print(car1 is car3)   # True  — same reference
print(car1 is car2)   # False — different objects

# id() returns memory address
print(id(car1))
print(id(car2))
print(id(car3))   # same as car1

# Type checking
print(type(car1))            # <class '__main__.Car'>
print(isinstance(car1, Car)) # True

🧩 Deleting Objects and Attributes

python example

car1 = Car("Toyota", "Camry", 2022)

# Delete an attribute
del car1.speed
# print(car1.speed)   # AttributeError!

# Delete the object reference
del car1
# print(car1)         # NameError!

del only deletes the reference. The actual object is garbage collected when no references remain.

📊 Summary Table

Concept	Description	Example
Class	Blueprint / template	`class Car:`
Object	Instance of class	`car1 = Car(...)`
Attribute	Data stored in object	`car1.speed`
Method	Function inside class	`car1.start()`
`self`	Reference to current instance	`self.name`
Class var	Shared across all instances	`Car.total_cars`
Instance var	Unique per object	`self.model`

🇮🇳 Hindi Explanation (हिंदी में समझें)

Class kya hai? A class is a template or blueprint that defines what data (attributes) an object will have and what it can do (methods).

Object kya hai? An object is a specific instance of a class — like multiple different items made from the same mold.

self kyon zaroori hai? self is used so that a method knows which specific object it's working on.

Class variable aur instance variable mein farq? A class variable is common across all instances (like a school's name), while an instance variable is unique to each object (like a student's name).

❓ Interview Questions

Q1: What is the difference between a class and an object?

Answer: A class is a blueprint or template that defines attributes and behaviors. An object is a concrete instance created from that class. You can create many objects from a single class, each with its own independent state.

Q2: What is `self` in Python? Is it a keyword?

Answer: self is a reference to the current instance of the class. It is not a Python keyword — it is a strong convention. When you call obj.method(), Python automatically passes the object as the first argument (self). You could technically name it anything, but self is universally used.

Q3: Difference between class variable and instance variable?

Answer:

Class variable: defined at class level, shared by all instances. Changing it affects all objects (unless overridden on the instance).
Instance variable: defined inside __init__ using self, unique to each object.

python example

class Demo:
    class_var = "shared"          # class variable
    def __init__(self):
        self.instance_var = "unique"  # instance variable

Q4: How does Python garbage collect objects?

Answer: Python uses reference counting. When an object's reference count drops to zero (no variable points to it), it is immediately deallocated. The gc module handles cyclic references that reference counting alone cannot resolve.

Q5: Can you add attributes to an object outside the class definition?

Answer: Yes. Python allows dynamic attribute assignment:

python example

car1 = Car("Toyota", "Camry", 2022)
car1.color = "Red"    # added dynamically
print(car1.color)     # Red

This is generally discouraged in production code — prefer defining all attributes in __init__.

Q6: What is the difference between `type()` and `isinstance()`?

Answer:

type(obj) == Car checks exact type — returns False for subclasses.
isinstance(obj, Car) returns True for the class and any subclass — preferred for type checking in OOP.

Q7: What happens when you call `del obj`?

Answer: del obj removes the name binding (reference), not the object itself. The object is garbage collected only when its reference count reaches zero (i.e., no other name or data structure holds a reference to it).

🧪 Practice Exercises

Library Book: Create a Book class with title, author, isbn, copies_available. Add checkout() and return_book() methods.
Temperature: Create a Temperature class that stores value in Celsius. Add methods to_fahrenheit() and to_kelvin().
Circle: Create a Circle class with radius. Add area(), circumference(), and is_unit_circle() methods.
Counter: Create a Counter class with increment(), decrement(), reset(), and value property. Track a class-level total_operations counter.
Student Report: Create a Student class that stores marks in 5 subjects. Add total(), average(), grade(), and is_pass() methods.

💡 Next Topic → Constructors: Dive deep into __init__, default arguments, class methods as alternate constructors, and __del__.

Exam Focus

Revise definitions, diagrams, examples, and short-answer points for Classes and Objects in Python.

Interview Use

Prepare one clear explanation, one practical example, and one common mistake for this Python Master Course topic.

Search Terms

python-master-course, python master course, python, master, course, object, oriented, programming

Continue learning this concept

Object Oriented ProgrammingAbstraction in PythonMaster abstraction in Python — abstract base classes (ABC), @abstractmethod, interface design, abstract properties, concrete vs abstract classes, and real-world design patterns.Object Oriented ProgrammingConstructors in PythonDeep dive into Python constructors — __init__, __new__, default parameters, class method constructors, constructor chaining, and destructor __del__ with real-world examples.Object Oriented ProgrammingEncapsulation in PythonLearn encapsulation in Python — public, protected, and private attributes, name mangling, getter/setter methods, the @property decorator, and data validation patterns.Object Oriented ProgrammingInheritance in PythonMaster Python inheritance — single, multiple, multilevel, and hierarchical inheritance, MRO (Method Resolution Order), super(), mixins, and real-world class hierarchies.Object Oriented ProgrammingMagic Methods (Dunder Methods) in PythonMaster Python Object Oriented ProgrammingMethod Overriding in PythonDeep dive into Python method overriding — redefining parent class methods in child classes, using super(), cooperative multiple inheritance, MRO interaction, and real-world design patterns.

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Python Notes

Classes and Objects in Python

Master the foundation of Object-Oriented Programming — learn how to define classes, create objects, use attributes and methods, and understand how Python models real-world entities as code.

🧠 Real-World Analogy — Blueprint aur Building

Think of an architect's blueprint — it's a design that specifies what the building will look like: how many floors, how many rooms, where the doors are. When a contractor builds an actual building from that blueprint — that's an object. From one blueprint, you can build thousands of different buildings — each with its own location, color, and address.

In Python:

Class = Blueprint (design / template)
Object = Actual instance built from that blueprint

📐 ASCII Class Diagram

text example

+---------------------------+
|         Car               |   ← Class Name
+---------------------------+
| - make: str               |   ← Attributes (data)
| - model: str              |
| - year: int               |
| - speed: float            |
+---------------------------+
| + start()                 |   ← Methods (behavior)
| + accelerate(amount)      |
| + brake()                 |
| + get_info() -> str       |
+---------------------------+

🚗 Example 1 — Defining a Class and Creating Objects

Example

Output:

Example

Toyota Camry engine started! 🚗 Speed increased to 60 km/h Speed increased to 100 km/h Braking... speed is now 80 km/h 2023 Honda Civic Total cars created: 3

🔍 Understanding `self`

self means "this object itself". When you call car1.start(), Python automatically passes car1 as self.

python example

# These two calls are IDENTICAL:
car1.start()          # ← short form (Python sugar)
Car.start(car1)       # ← explicit form (shows what really happens)

self is NOT a keyword — it is a convention. You could name it anything, but always use self.

🏗️ Class Variables vs Instance Variables

python example

class Student:
    school_name = "WoHoTech Academy"   # ← class variable (shared)

    def __init__(self, name, grade):
        self.name = name               # ← instance variable (unique)
        self.grade = grade

    def introduce(self):
        print(f"Hi, I'm {self.name}, grade {self.grade} at {Student.school_name}")


s1 = Student("Arjun", 10)
s2 = Student("Priya", 11)

s1.introduce()
s2.introduce()

# Changing class variable affects ALL instances
Student.school_name = "WoHoTech Global Academy"
s1.introduce()   # updated!
s2.introduce()   # updated!

# Changing instance variable affects ONLY that instance
s1.name = "Arjun Kumar"
print(s1.name)   # Arjun Kumar
print(s2.name)   # Priya  (unchanged)

Output:

Example

🏦 Example 2 — Bank Account

python example

class BankAccount:
    bank_name = "WoHo National Bank"
    interest_rate = 0.04   # 4% annual

    def __init__(self, owner, balance=0):
        self.owner = owner
        self._balance = balance       # convention: _ means "protected"
        self.transactions = []

    def deposit(self, amount):
        if amount <= 0:
            print("❌ Deposit amount must be positive.")
            return
        self._balance += amount
        self.transactions.append(f"+₹{amount}")
        print(f"✅ Deposited ₹{amount}. New balance: ₹{self._balance}")

    def withdraw(self, amount):
        if amount > self._balance:
            print(f"❌ Insufficient funds. Balance: ₹{self._balance}")
            return
        self._balance -= amount
        self.transactions.append(f"-₹{amount}")
        print(f"✅ Withdrew ₹{amount}. New balance: ₹{self._balance}")

    def get_balance(self):
        return self._balance

    def add_interest(self):
        interest = self._balance * BankAccount.interest_rate
        self._balance += interest
        print(f"💰 Interest added: ₹{interest:.2f}. New balance: ₹{self._balance:.2f}")

    def statement(self):
        print(f"\n{'='*40}")
        print(f"  {BankAccount.bank_name}")
        print(f"  Account holder: {self.owner}")
        print(f"  Balance: ₹{self._balance}")
        print(f"  Transactions: {', '.join(self.transactions)}")
        print(f"{'='*40}\n")


acc1 = BankAccount("Rahul Sharma", 10000)
acc2 = BankAccount("Sneha Gupta", 5000)

acc1.deposit(2000)
acc1.withdraw(500)
acc1.add_interest()
acc1.statement()

acc2.withdraw(6000)   # should fail
acc2.deposit(1000)
acc2.statement()

Output:

✅ Deposited ₹2000. New balance	₹12000
✅ Withdrew ₹500. New balance	₹11500
💰 Interest added	₹460.00. New balance: ₹11960.00
Account holder	Rahul Sharma
Balance	₹11960.0
Transactions	+₹2000, -₹500
❌ Insufficient funds. Balance	₹5000
✅ Deposited ₹1000. New balance	₹6000
Account holder	Sneha Gupta
Balance	₹6000
Transactions	+₹1000

📦 Example 3 — Product Inventory

Example

Output:

[PRD-1000] Python Book \| Price	₹ 599.00 \| Qty: 50
[PRD-1001] USB-C Cable \| Price	₹ 299.00 \| Qty: 120
[PRD-1002] Laptop Stand \| Price	₹ 1499.00 \| Qty: 30
[PRD-1003] Mechanical Keyboard \| Price	₹ 3499.00 \| Qty: 15
Restocked 20 units of 'Laptop Stand'. Total	50
[PRD-1000] Python Book \| Price	₹ 599.00 \| Qty: 40
[PRD-1001] USB-C Cable \| Price	₹ 299.00 \| Qty: 120
[PRD-1002] Laptop Stand \| Price	₹ 1499.00 \| Qty: 50
[PRD-1003] Mechanical Keyboard \| Price	₹ 3499.00 \| Qty: 15
Total inventory value	₹1,37,745.00

🔬 Object Identity, Equality and Type

python example

car1 = Car("Toyota", "Camry", 2022)
car2 = Car("Toyota", "Camry", 2022)
car3 = car1   # same reference!

# Identity (same object in memory?)
print(car1 is car3)   # True  — same reference
print(car1 is car2)   # False — different objects

# id() returns memory address
print(id(car1))
print(id(car2))
print(id(car3))   # same as car1

# Type checking
print(type(car1))            # <class '__main__.Car'>
print(isinstance(car1, Car)) # True

🧩 Deleting Objects and Attributes

python example

car1 = Car("Toyota", "Camry", 2022)

# Delete an attribute
del car1.speed
# print(car1.speed)   # AttributeError!

# Delete the object reference
del car1
# print(car1)         # NameError!

del only deletes the reference. The actual object is garbage collected when no references remain.

📊 Summary Table

Concept	Description	Example
Class	Blueprint / template	`class Car:`
Object	Instance of class	`car1 = Car(...)`
Attribute	Data stored in object	`car1.speed`
Method	Function inside class	`car1.start()`
`self`	Reference to current instance	`self.name`
Class var	Shared across all instances	`Car.total_cars`
Instance var	Unique per object	`self.model`

🇮🇳 Hindi Explanation (हिंदी में समझें)

Class kya hai? A class is a template or blueprint that defines what data (attributes) an object will have and what it can do (methods).

Object kya hai? An object is a specific instance of a class — like multiple different items made from the same mold.

self kyon zaroori hai? self is used so that a method knows which specific object it's working on.

Class variable aur instance variable mein farq? A class variable is common across all instances (like a school's name), while an instance variable is unique to each object (like a student's name).

❓ Interview Questions

Q1: What is the difference between a class and an object?

Q2: What is `self` in Python? Is it a keyword?

Q3: Difference between class variable and instance variable?

Answer:

Class variable: defined at class level, shared by all instances. Changing it affects all objects (unless overridden on the instance).
Instance variable: defined inside __init__ using self, unique to each object.

python example

class Demo:
    class_var = "shared"          # class variable
    def __init__(self):
        self.instance_var = "unique"  # instance variable

Q4: How does Python garbage collect objects?

Q5: Can you add attributes to an object outside the class definition?

Answer: Yes. Python allows dynamic attribute assignment:

python example

car1 = Car("Toyota", "Camry", 2022)
car1.color = "Red"    # added dynamically
print(car1.color)     # Red

This is generally discouraged in production code — prefer defining all attributes in __init__.

Q6: What is the difference between `type()` and `isinstance()`?

Answer:

type(obj) == Car checks exact type — returns False for subclasses.
isinstance(obj, Car) returns True for the class and any subclass — preferred for type checking in OOP.

Q7: What happens when you call `del obj`?

🧪 Practice Exercises

Library Book: Create a Book class with title, author, isbn, copies_available. Add checkout() and return_book() methods.
Temperature: Create a Temperature class that stores value in Celsius. Add methods to_fahrenheit() and to_kelvin().
Circle: Create a Circle class with radius. Add area(), circumference(), and is_unit_circle() methods.
Counter: Create a Counter class with increment(), decrement(), reset(), and value property. Track a class-level total_operations counter.
Student Report: Create a Student class that stores marks in 5 subjects. Add total(), average(), grade(), and is_pass() methods.

💡 Next Topic → Constructors: Dive deep into __init__, default arguments, class methods as alternate constructors, and __del__.

Exam Focus

Revise definitions, diagrams, examples, and short-answer points for Classes and Objects in Python.

Interview Use

Prepare one clear explanation, one practical example, and one common mistake for this Python Master Course topic.

Search Terms

python-master-course, python master course, python, master, course, object, oriented, programming

Continue learning this concept

PreviousAbstraction in Python NextConstructors in Python

[PRD-1000] Python Book \| Price	₹ 599.00 \| Qty: 50
[PRD-1001] USB-C Cable \| Price	₹ 299.00 \| Qty: 120
[PRD-1002] Laptop Stand \| Price	₹ 1499.00 \| Qty: 30
[PRD-1003] Mechanical Keyboard \| Price	₹ 3499.00 \| Qty: 15
Restocked 20 units of 'Laptop Stand'. Total	50
[PRD-1000] Python Book \| Price	₹ 599.00 \| Qty: 40
[PRD-1001] USB-C Cable \| Price	₹ 299.00 \| Qty: 120
[PRD-1002] Laptop Stand \| Price	₹ 1499.00 \| Qty: 50
[PRD-1003] Mechanical Keyboard \| Price	₹ 3499.00 \| Qty: 15
Total inventory value	₹1,37,745.00

[PRD-1000] Python Book \| Price	₹ 599.00 \| Qty: 50
[PRD-1001] USB-C Cable \| Price	₹ 299.00 \| Qty: 120
[PRD-1002] Laptop Stand \| Price	₹ 1499.00 \| Qty: 30
[PRD-1003] Mechanical Keyboard \| Price	₹ 3499.00 \| Qty: 15
Restocked 20 units of 'Laptop Stand'. Total	50
[PRD-1000] Python Book \| Price	₹ 599.00 \| Qty: 40
[PRD-1001] USB-C Cable \| Price	₹ 299.00 \| Qty: 120
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🧠 Real-World Analogy — Blueprint aur Building

📐 ASCII Class Diagram

🚗 Example 1 — Defining a Class and Creating Objects

🔍 Understanding self

🏗️ Class Variables vs Instance Variables

🏦 Example 2 — Bank Account

📦 Example 3 — Product Inventory

🔬 Object Identity, Equality and Type

🧩 Deleting Objects and Attributes

📊 Summary Table

🇮🇳 Hindi Explanation (हिंदी में समझें)

❓ Interview Questions

Q1: What is the difference between a class and an object?

Q2: What is self in Python? Is it a keyword?

Q3: Difference between class variable and instance variable?

Q4: How does Python garbage collect objects?

Q5: Can you add attributes to an object outside the class definition?

Q6: What is the difference between type() and isinstance()?

Q7: What happens when you call del obj?

🧪 Practice Exercises

Continue learning this concept

🧠 Real-World Analogy — Blueprint aur Building

📐 ASCII Class Diagram

🚗 Example 1 — Defining a Class and Creating Objects

🔍 Understanding self

🏗️ Class Variables vs Instance Variables

🏦 Example 2 — Bank Account

📦 Example 3 — Product Inventory

🔬 Object Identity, Equality and Type

🧩 Deleting Objects and Attributes

📊 Summary Table

🇮🇳 Hindi Explanation (हिंदी में समझें)

❓ Interview Questions

Q1: What is the difference between a class and an object?

Q2: What is self in Python? Is it a keyword?

Q3: Difference between class variable and instance variable?

Q4: How does Python garbage collect objects?

Q5: Can you add attributes to an object outside the class definition?

Q6: What is the difference between type() and isinstance()?

Q7: What happens when you call del obj?

🧪 Practice Exercises

Continue learning this concept

🔍 Understanding `self`

Q2: What is `self` in Python? Is it a keyword?

Q6: What is the difference between `type()` and `isinstance()`?

Q7: What happens when you call `del obj`?

🔍 Understanding `self`

Q2: What is `self` in Python? Is it a keyword?

Q6: What is the difference between `type()` and `isinstance()`?

Q7: What happens when you call `del obj`?