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Python Classes Explained

OOP Core

Defining Classes in Python

Classes package related data and behavior. Master syntax, attributes, and method definitions here.

Create your first classJump to __init__

Basics​

class Invoice:
    currency = "USD"  # class attribute

    def __init__(self, total: float, customer: str):
        self.total = total
        self.customer = customer

    def apply_discount(self, percent: float) -> None:
        self.total *= 1 - percent
  • class keyword introduces the definition.
  • Methods accept self as the first argument (the instance).
  • Use docstrings to describe purpose and parameters.

Attributes​

  • Instance attributes live on each object (self.total).
  • Class attributes live on the class itself and are shared unless overridden.
  • Leverage @property to create computed attributes with read-only semantics.

Next up in your learning path

Create objects

Understand how instances differ from classes.

Companion

__init__ method

Control how classes initialize state.

Next topic

Encapsulation

Hide implementation details and expose APIs.

Design