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1. Create Class & Object2. Instance vs Class Variables3. Constructors in Python Classes4. Single Inheritance5. Multiple Inheritance6. Multilevel Inheritance7. Polymorphism with Methods8. Method Overloading Simulation9. Encapsulation with Getters/Setters10. Abstraction with ABC11. Operator Overloading12. Custom Iterator13. Class Methods14. Static Methods15. Composition Example16. Aggregation Example17. Private Variables18. Magic Methods Overview19. Object Cloning20. Custom Exceptions21. Class Decorator22. Prototype Pattern23. Singleton Pattern24. MRO (Method Resolution Order) Demo25. Polymorphism (Duck Typing)

Private Variables in Python

Use name-mangling with double underscores to indicate private attributes.

IntermediateObject-Oriented ProgramsExample 17 of 25
private-variables.py
1# Program to demonstrate private variables (name mangling)
2

3class Secret:
4    def __init__(self, data):
5        self.__data = data
6

7    def reveal(self):
8        print("Secret is:", self.__data)
9

10s = Secret("hidden")
11s.reveal()
12

13# Direct access would fail: s.__data

Output

Secret is: hidden

What's going on

Attributes starting with __ are name-mangled to _ClassName__attr, discouraging external access.

After this program

If the idea is still fuzzy, read Day 11: Classes and Objects in the Python course. For a short check, try the Python quiz (300 questions). Stay with all 25 object-oriented programs, or see every topic on Python exercises.

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