Encapsulation

What is Encapsulation?

Encapsulation is about restricting access to parts of your code (data or methods), exposing only what is necessary. This keeps your code safe and easier to manage.

In Python, we use underscores (_ or __) to indicate that attributes or methods are private (should not be accessed directly).

Basic Example

class User:
    def __init__(self, username, password):
        self.username = username
        self.__password = password  # private attribute

    def check_password(self, password):
        return self.__password == password

user = User("alice", "secret123")
print(user.username)          # Output: alice
print(user.check_password("wrong"))  # Output: False
# print(user.__password)     # Error: attribute is private

Real World Use Cases

• Banking Apps: User account balance is kept private; access is only via methods like deposit() or withdraw().

• Medical Systems: Patient details are hidden and only accessible through secure methods.

• APIs: You hide internal logic and only expose certain functions to users.

Key Points

• Use underscores to indicate private variables or methods.

• Protects data and reduces bugs by preventing unauthorized access.

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