Learn Web Development with Python

Initializing an instance

Have you noticed how, before calling p1.final_price(...), we had to assign net_price to p1? There is a better way to do it. In other languages, this would be called a constructor, but in Python, it's not. It is actually an initializer, since it works on an already-created instance, and therefore it's called __init__. It's a magic method, which is run right after the object is created. Python objects also have a __new__ method, which is the actual constructor. In practice, it's not so common to have to override it though, it's a practice that is mostly used when coding metaclasses, which as we mentioned, is a fairly advanced topic that we won't explore in the book:

# oop/class.init.pyclass Rectangle: def __init__(self, ...