Object-Oriented Programming (OOP) lets us model real-world things as code. In this tutorial, we’ll use a Bank Account to demonstrate how to use OOP concepts in Python.
Step 1: Define the Class
We’ll start by creating a simple BankAccount class with a few attributes.
class BankAccount:
def __init__(self, owner, balance=0):
self.owner = owner
self.balance = balanceStep 2: Add Methods
Now let’s add some basic functionality: deposit, withdraw, and check balance.
class BankAccount:
def __init__(self, owner, balance=0):
self.owner = owner
self.balance = balance
def deposit(self, amount):
if amount > 0:
self.balance += amount
print(f"Deposited ${amount}. New balance: ${self.balance}")
else:
print("Deposit amount must be positive.")
def withdraw(self, amount):
if amount > self.balance:
print("Insufficient funds.")
else:
self.balance -= amount
print(f"Withdrew ${amount}. New balance: ${self.balance}")
def display_balance(self):
print(f"{self.owner}'s account balance: ${self.balance}")Step 3: Create and Use an Object
We’ll start by creating a simple BankAccount class with a few attributes.
account1 = BankAccount("Alice", 100)
account1.display_balance() # Alice's account balance: $100
account1.deposit(50) # Deposited $50. New balance: $150
account1.withdraw(30) # Withdrew $30. New balance: $120
account1.withdraw(200) # Insufficient funds.Step 4: Inheritance (Advanced Concept)
Let’s say we want a SavingsAccount that earns interest. We can extend the BankAccount class.
class SavingsAccount(BankAccount):
def __init__(self, owner, balance=0, interest_rate=0.02):
super().__init__(owner, balance)
self.interest_rate = interest_rate
def apply_interest(self):
interest = self.balance * self.interest_rate
self.balance += interest
print(f"Interest applied: ${interest:.2f}. New balance: ${self.balance:.2f}")
savings = SavingsAccount("Bob", 1000)
savings.display_balance() # Bob's account balance: $1000
savings.apply_interest() # Interest applied: $20.00. New balance: $1020.00