Decorators in Python

 

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Decorators in Python

Decorators in Python are a powerful tool that allow you to modify the behavior of functions or classes. A decorator is a function that takes another function as an argument and extends or alters its behavior. They are often used for logging, access control, instrumentation, caching, and more.

1. Function Decorators

Function decorators are defined using the @decorator_name syntax. They can add functionality to an existing function without modifying its structure.

Example:

# Define a decorator
def my_decorator(func):
    def wrapper():
        print('Something is happening before the function is called.')
        func()
        print('Something is happening after the function is called.')
    return wrapper

# Apply the decorator
@my_decorator
def say_hello():
    print('Hello!')

# Call the decorated function
say_hello()
    

Output:

Something is happening before the function is called.
Hello!
Something is happening after the function is called.
    

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2. Decorators with Arguments

Decorators can also accept arguments, which allows for even more flexibility.

Example:

# Define a decorator with arguments
def repeat(num_times):
    def decorator_repeat(func):
        def wrapper(*args, **kwargs):
            for _ in range(num_times):
                func(*args, **kwargs)
        return wrapper
    return decorator_repeat

# Apply the decorator with arguments
@repeat(3)
def greet(name):
    print(f'Hello, {name}!')

# Call the decorated function
greet('Alice')
    

Output:

Hello, Alice!
Hello, Alice!
Hello, Alice!
    

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Decorators are a key part of Python, enabling you to write cleaner, more maintainable, and more reusable code.