A decorator in Python is one of the most powerful tools that enhance the function behavior, method, or class without modifying its actual structure or code. Moreover, decorators are applied before the function definition to alter or extend its behavior. This blog will explain how decorators are effectively used in Python Functions.
Before moving to decorators, we must have a clear understanding of the functions in Python.
Functions in Python are blocks of reusable code that are executed multiple times whenever they are called. Functions can break the code into one or more manageable pieces for better understanding and readability.
Table of Contents
Assigning function to Variable
Functions are first-class objects, meaning you can assign a function to a variable, pass it as an argument, and return from another function
When the function is assigned to a variable, you can call the function through that variable, just like the original function name
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Nested function
A nested function is a function that is defined inside another function, and the inner function can access the variables and methods present in the outer function. This approach helps in organizing the code in a more structured and encapsulated way
def outer_fun(x):
z = 10
def inner_fun(y):
return x+y+z
return inner_fun
add_num = outer_fun(10)
print(add_num(4))
Passing Functions as Argument to Other Functions
Functions are first-class objects, meaning you can pass a function to another function as an argument This allows for creating higher-order functions, making the code reusable and flexible.
Return a Function as a Value
As we have already discussed, functions are first-class objects, meaning you can return a function from another defined function. This allows you to create a dynamic function that changes the behavior according to parameters or context
Decorators
A decorator is used to modify the behavior or enhance capabilities without modifying the existing code or structure. They can be thought of as wrappers that enhance the functionality of a function or method. This allows for achieving code reusability and modularity.
A decorator takes an input function, wraps it with additional functionality, and returns the enhanced version of that function.
In Python, anything that can be called like a function with parentheses () is something known as a callable. this includes methods, functions, and even objects that implement the __call__() method. Since decorators are themselves functions, they are callable and can be used to modify other callables.
add_new(func) is a decorator that takes a function (normal_func) and adds extra functionality (added extra things) before calling the original function. When the decorator_func() is called, first it prints (added extra things) and then calls the normal_func() which prints “this is normal.”
@symbol with decorator
The @symbol is used to perform decorator with function. It is a short way of writing the decorator that makes the code cleaner and easier to understand. Essentially, it directly applies the decorator to the function it’s decorating without needing to call the decorator explicitly.
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Passing Argument to the Decorator
A Python decorator with arguments accepts additional arguments alongside its function decorator. This is beneficial when you want the decorator to modify its behavior based on external inputs.
Common built-in decorators in Python
Here are some built-in decorators in Python :
@staticmethod
This @staticmethod does not require or depend on the instance or class to be called for execution. This means @staticmethod can be called without creating any object or instance of the class, i.e., it can be called directly using the class name.
@classmethod
@classmethod is a method that is bound to the class itself rather than the instance. In regular methods, we take self as a first parameter, but @classmethod takes cls as the first parameter, which refers to the class itself. This allows the method to modify the class-level data and its properties, and it can be called from the class or an instance of the class.
@property
This @property decorator defines a method as a property, meaning it allows you to define a method that behaves as an attribute. You can access it as if it were a simple variable without needing to call it explicitly as a method(without parentheses).
Chaining decorators
Chaining decorators refers to applying multiple decorators to one function or method, one after another. Every decorator wraps the function and enhances or modifies its behavior.
Watch the video below to learn more about decorators
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Conclusion
Python decorators are one of the prominent aspects of functions that help you add functionality to your function for the enhancement of the existing version without modifying the actual code. They tend to make your code modular, avoid duplication, and improve readability. If you want to learn more about Python, then do check out our latest Python course.