Classes and Objects

A class is a blueprint for creating objects that bundle data and behavior together.

class Student:
    def __init__(self, name, xp=0):
        self.name = name
        self.xp = xp

    def gain_xp(self, amount):
        self.xp += amount
        return self.xp

ada = Student("Ada")
ada.gain_xp(50)
print(f"{ada.name} has {ada.xp} XP")

grace = Student("Grace", xp=10)
grace.gain_xp(5)
print(f"{grace.name} has {grace.xp} XP")

Key pieces

• __init__ is the constructor, it runs automatically whenever you create a new instance with Student(...).
• self refers to the specific instance a method was called on, it's always the first parameter of an instance method.
• Each instance (ada, grace) keeps its own independent copy of the data set in __init__.