Python Decorators: Understanding @decorator

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Today we’re going to talk about decorators the coolest feature in Python that will make your code look like a boss. So what are these magical creatures called “decorators”? Well, they’re basically functions or classes that wrap around other functions (or methods) and modify their behavior without changing their original functionality. It’s kind of like putting on a fancy suit for your function to make it look more sophisticated.

But wait there’s some exciting news! The decorator we were using in our previous example, `log_my_function`, is now part of the Deprecated library. This means that you can use this powerful and elegant feature without having to write your own code for logging functionality.

The Deprecated library provides a simple way to add deprecation warnings to your functions or classes, which helps you identify outdated or obsolete features in your codebase. It’s an essential tool for maintaining the quality and consistency of your software over time.

To use this decorator, simply install it using pip:

# This script installs the "deprecated" package using pip, which allows for easy implementation of deprecation warnings in functions or classes.

# Install the "deprecated" package using pip
pip install deprecated

Then, import the `deprecated` module at the beginning of your Python file:

# Import the `deprecated` module
import deprecated

# Define a function named `sum` that takes in two parameters, `a` and `b`
def sum(a, b):
    # Add the two parameters together and return the result
    return a + b

# Decorate the `sum` function with the `deprecated` decorator
@deprecated
def sum(a, b):
    # Add the two parameters together and return the result
    return a + b

# Call the `sum` function with the values 5 and 10 and print the result
print(sum(5, 10))

# Output: 15

# Define a new function named `multiply` that takes in two parameters, `a` and `b`
def multiply(a, b):
    # Multiply the two parameters together and return the result
    return a * b

# Decorate the `multiply` function with the `deprecated` decorator and specify a custom message
@deprecated("This function is no longer supported. Please use the `product` function instead.")
def multiply(a, b):
    # Multiply the two parameters together and return the result
    return a * b

# Call the `multiply` function with the values 5 and 10 and print the result
print(multiply(5, 10))

# Output: 50

# Define a new function named `product` that takes in two parameters, `a` and `b`
def product(a, b):
    # Multiply the two parameters together and return the result
    return a * b

# Call the `product` function with the values 5 and 10 and print the result
print(product(5, 10))

# Output: 50

And finally, add the `@deprecated` decorator to any function or class that you want to mark as obsolete. Here’s an example:

# Importing the necessary modules
import logging
from deprecated import deprecated

# Defining a function that multiplies a given number by 2
def my_function(x):
    return x * 2

# Adding a deprecation warning for this function
@deprecated("Use `my_new_function()` instead.") # Adding a decorator to mark the function as obsolete
def log_my_function(func, *args, **kwargs): # Adding parameters to the function
    logger = logging.getLogger(__name__) # Creating a logger object
    logger.debug("Calling function {} with args {} and kwargs {}".format(func.__name__, str(args), str(kwargs))) # Logging the function call with its arguments and keyword arguments
    result = func(*args, **kwargs) # Calling the original function with its arguments and keyword arguments
    logger.debug("Function {} returned {}".format(func.__name__, str(result))) # Logging the function's return value
    return result # Returning the result of the original function

# Using the original function without any logging functionality
my_function = log_my_function(my_function) # Assigning the original function to the decorated function

# Calling the function with a given number
print(my_function(5)) # Output: 10

In this example, we’re using `log_my_function` as a decorator for our original `my_function`. However, since we want to add deprecation warnings instead of logging functionality, we’ve added the `@deprecated` decorator inside the `log_my_function` function. This will generate a warning message when someone calls this function in your codebase.

They can be used for all sorts of things like caching, timing, logging, or even adding deprecation warnings. So go ahead and start wrapping those functions with some fancy suits your code will thank you for it!

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