What are some examples of the decorator pattern in Python?

Can you explain the decorator pattern in Python with some examples?

Sure! The decorator pattern allows you to add new functionality to an existing object without modifying its structure. In Python, decorators are often used to modify the behavior of functions or methods.

Can you show me a simple example of a function decorator?

Absolutely! Here's a simple function decorator that logs the execution time of a function:

import time

def timer_decorator(func):
    def wrapper(*args, **kwargs):
        start_time = time.time()
        result = func(*args, **kwargs)
        end_time = time.time()
        print(f"{func.__name__} executed in {end_time - start_time} seconds")
        return result
    return wrapper

@timer_decorator
def my_function():
    time.sleep(1)
    print("Function executed")

my_function()

What about class decorators? Can you give an example?

Sure! Here's an example of a class decorator that adds a greeting method to a class:

def add_greeting(cls):
    cls.greet = lambda self: f"Hello, {self.name}!"
    return cls

@add_greeting
class Person:
    def __init__(self, name):
        self.name = name

p = Person("Alice")
print(p.greet())  # Output: Hello, Alice!

Are there any built-in decorators in Python?

Yes, Python has several built-in decorators like @staticmethod, @classmethod, and @property that are commonly used in class definitions.