chapter_13_classes_objects

Chapter 13: Classes and Objects

Until now, we've used Python's built-in types (strings, lists, dictionaries). This chapter introduces the ability to create our own programmer-defined types using classes.

Core Concepts

• Class: A blueprint or template for a user-defined type.
• Instance: A specific object created from a class.
• Instantiation: The process of creating a new object.
• Attributes: Named values associated with an object (e.g., p.x and p.y).
• State: The values of an object's attributes at a given time.

Engineering Takeaways

• Classes vs Instances: A class is like the concept of a "Car". An instance is your specific Honda Civic parked outside.
• Objects are Mutable: By default, you can change the state of an object by reassigning its attributes. This is powerful but requires careful tracking of aliasing.
• Copying: Because objects are mutable, aliasing (p1 = p2) can lead to bugs. Use the copy module (copy.copy() or copy.deepcopy()) to create independent clones of objects.