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Mastering Python Decorators: A Complete Information to Superior Utilization


Introduction

Python decorators are a strong characteristic that means that you can modify the conduct of features or lessons dynamically. Decorators present a approach so as to add performance to present code with out modifying the unique supply. This weblog put up will delve into the idea of decorators in Python, ranging from the fundamentals and steadily progressing to extra superior strategies.

Understanding Decorators

Operate Decorators

Operate decorators are a strategy to modify the conduct of a perform by wrapping it inside one other perform. The decorator perform takes the unique perform as an argument, provides some performance, and returns a modified perform. This lets you improve or prolong the conduct of features with out modifying their supply code.

def uppercase_decorator(func):
    def wrapper():
        end result = func()
        return end result.higher()
    return wrapper

@uppercase_decorator
def say_hello():
    return "Howdy, World!"

print(say_hello())  # Output: HELLO, WORLD!

Within the instance above, the uppercase_decorator perform is outlined to wrap the say_hello perform. It modifies the conduct by changing the returned string to uppercase. The @uppercase_decorator syntax is used to use the decorator to the say_hello perform.

Class Decorators

Class decorators are just like perform decorators however function on lessons as an alternative of features. They assist you to modify the conduct or add performance to a category. The decorator perform takes the unique class as an argument, creates a derived class with added performance, and returns the modified class.

def add_method_decorator(cls):
    def new_method(self):
        return "New methodology added!"
    cls.new_method = new_method
    return cls

@add_method_decorator
class MyClass:
    def existing_method(self):
        return "Present methodology referred to as!"

obj = MyClass()
print(obj.existing_method())  # Output: Present methodology referred to as!
print(obj.new_method())  # Output: New methodology added!

Within the instance above, the add_method_decorator perform wraps the MyClass class and provides a brand new methodology referred to as new_method. The @add_method_decorator syntax is used to use the decorator to the MyClass class.

Decorator Syntax and Execution

When utilizing decorators, it’s vital to know the order of execution. Decorators are utilized from the underside up, which means the decorator outlined on the high is executed final. This order is essential when a number of decorators are utilized to the identical perform or class.

def decorator1(func):
    print("Decorator 1 executed")
    return func

def decorator2(func):
    print("Decorator 2 executed")
    return func

@decorator1
@decorator2
def my_function():
    print("Inside my_function")

my_function()

Output:

Decorator 2 executed
Decorator 1 executed
Inside my_function

Within the instance above, the decorator2 decorator is executed first, adopted by the decorator1 decorator. The my_function is then referred to as, and the output displays the order of execution.

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