Chapter 9 – Classes
- object-oriented programming (OOP) – is one of the most effective approaches to writing software
- classes – used in object-oriented programming to represent real-world things and situations
- objects – created based on these classes, general behavior defined when class is written
- instantiation – making an object from a class
- instances – created for classes to store information, with defined actions that can be taken
- object-oriented programming will help you see the world as a programmer does
Creating and using a class
- classes can model almost anything
- For example, a simple class, Dog, can represent any dog, can contain two pieces of information (name and age) and two behaviors (sit and roll over)
Creating the dog class
- each instance created from the Dog class will store a name and an age, and will give each dog the ability to sit() and roll_over()
dog.py
class Dog:
….”””A simple attempt to model a dog.”””
….def_init_(self, name, age):
……..”””Initialize name and age attributes.”””
……..self.name = name
……..self.age = age
….def sit(self):
……..”””Simulate a dog sitting in response to a command.”””
……..print(f”{self.name} is now sitting.”)
….def roll_over(self):
……..”””Simulate rolling over in response to a command.”””
……..print(f”{self.name} rolled over!”)
- first defined a class called Dog (capital names refer to classes in Python by default)
- no parentheses in the class definition because the class is created from scratch
- then write a docstring describing what this class does
End of study session.