Next
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)

Aggregation Example in Python

Pass an existing object in. The other class uses it; it does not create it.

IntermediateObject-Oriented ProgramsExample 16 of 25
aggregation-example.py
1# Program to demonstrate aggregation
2

3class Team:
4    def __init__(self, name):
5        self.name = name
6

7class Player:
8    def __init__(self, name, team: Team):
9        self.name = name
10        self.team = team
11

12t = Team("Tigers")
13p = Player("Alice", t)
14

15print(p.name, "plays for", p.team.name)

Output

Alice plays for Tigers

What's going on

The Player has a reference to a Team that may outlive or be shared with other players (aggregation).

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.

PreviousComposition ExampleNextPrivate Variables