5 Practical Examples to Master Python Decorators

 

5. Decorator for Timing

A decorator to measure the execution time of a function.

import time

def timer(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

def slow_function():

    time.sleep(2)

    return "Finished"

print(slow_function())

#clcoding.com

slow_function executed in 2.001049518585205 seconds

Finished

4. Decorator for Caching

A decorator to cache the results of expensive function calls.

def cache(func):

    cached_results = {}

    def wrapper(*args):

        if args in cached_results:

            return cached_results[args]

        result = func(*args)

        cached_results[args] = result

        return result

    return wrapper

@cache

def slow_function(x):

    print(f"Computing {x}...")

    return x * x

print(slow_function(4))

print(slow_function(4))

print(slow_function(5))

#clcoding.com

Computing 4...

16

16

Computing 5...

25

3. Decorator for Logging

A decorator to log function calls and their arguments.

def logger(func):

    def wrapper(*args, **kwargs):

        print(f"Function {func.__name__} called with args: {args} and kwargs: {kwargs}")

        result = func(*args, **kwargs)

        print(f"Function {func.__name__} returned {result}")

        return result

    return wrapper

@logger

def add(a, b):

    return a + b

add(3, 5)

#clcoding.com

Function add called with args: (3, 5) and kwargs: {}

Function add returned 8

8

2. Decorator with Arguments

A decorator that accepts arguments to customize its behavior.

def repeat(n):

    def decorator(func):

        def wrapper(*args, **kwargs):

            for _ in range(n):

                func(*args, **kwargs)

        return wrapper

    return decorator

@repeat(3)

def greet(name):

    print(f"Hello, {name}!")

greet("Clcoding")

#clcoding.com

Hello, Clcoding!

Hello, Clcoding!

Hello, Clcoding!

1. Basic Decorator

A simple example to understand the basic structure and functionality of decorators.

def simple_decorator(func):

    def wrapper():

        print("Before the function runs")

        func()

        print("After the function runs")

    return wrapper

@simple_decorator

def say_hello():

    print("Hello!")

say_hello()

#clcoding.com

Before the function runs

Hello!

After the function runs