Python, being a language that values simplicity and readability, offers a powerful feature known as decorators.
These allow developers to wrap functions or methods, thereby extending or modifying their behavior without permanently modifying them.
This article explores the core concepts of decorators in Python, backed by illustrative code examples.
At its essence, a decorator is a callable (function, method, or class) that takes another callable as an argument and returns a new callable that carries the extended or modified behavior.
Let's break down those concepts:
- Callable: In Python, a callable is something that can be called. This primarily includes functions, methods (functions defined inside classes), and classes (which when called, instantiate new objects). They are known as callables because you can "call" them using parentheses to execute them.
- Takes another callable as an argument: Decorators are designed to take another callable as an argument. This means when you create a decorator, it's set up to receive a function, method, or class, which it will then do something with.
- Returns a new callable: After receiving the initial callable, the decorator then returns a new callable. This new callable is usually a modified or extended version of the original callable. This is where the magic of decorators comes into play - they allow you to "decorate" or "wrap" a function with additional behavior.
- Carries the extended or modified behavior: The new callable returned by the decorator carries some extended or modified behavior compared to the original callable. This is the essence of what decorators do: they allow you to add on to or change the behavior of functions, methods, or classes, without altering the original callables themselves.
The syntax to apply a decorator is to prefix the decorated function with