Decorators in Python

Decorators in Python
Python Notes:
In Python, a decorator is a design pattern that allows you to extend or modify the behavior of functions or methods without changing their code. Decorators are often used to add functionality to functions or methods, such as logging, authentication, or performance monitoring.

Decorators are a powerful tool in Python for code reuse, separation of concerns, and adding functionality to functions or methods in a clean and modular way. Python also provides several built-in decorators (e.g., @staticmethod, @classmethod, @property) and libraries often use decorators for various purposes, such as web frameworks (e.g., Flask and Django) using decorators for route handling and authentication.

Functions
Functions are first-class objects in the Python because they can reference to, passed to a variable and returned from other functions as well

# Function
def getSalary(employeeName):
if employeeName == 'Raj':
return 10000
elif employeeName == 'Rohan':
return 15000
else:
return 0
print(getSalary('Raj'))
getSalary1 = getSalary
print(getSalary1('Rohan'))

Python provides the facility to define the function inside another function. These types of functions are called inner functions

# Inner Function -1
def getSalary():
salary = 0
bonus = 0
def getBasicSalary():
return 1000
def getBonus():
return 2000
salary = getBasicSalary()
bonus = getBonus()
return salary + bonus

print(getSalary())


A function that accepts other function as an argument is also called higher order function. Consider the following example:


Inner Function - 2
Decorating functions with parameters
In Decorators, functions are passed as an argument into another function and then called inside the wrapper function.


Let's have an example to understand the parameterized decorator function:

def TrackingSalary(name):
return f'Salary found for { name }'
def Wrapper(fun):
def getSalary(x):
salary = 0
bonus = 0
track = fun(x)

def getBasicSalary():
return 1000

def getBonus():
return 2000

salary = getBasicSalary()
bonus = getBonus()

print(track)
return salary + bonus
return getSalary

w1 = Wrapper(TrackingSalary)
print(w1('Raj'))

Syntactic Decorator
In the above program, we have decorated out_div() that is little bit bulky. Instead of using above method, Python allows to use decorator in easy way with @symbol. Sometimes it is called "pie" syntax.

def BasicDetails(fun):
print(f'{ fun.__name__ } called ')
def inner(*args, **kwargs):
return fun(*args, **kwargs)
return inner

@BasicDetails
def getEmployeeSalary(name):
salary = 0
bonus = 0

def getBasicSalary():
return 1000

def getBonus():
return 2000

salary = getBasicSalary()
bonus = getBonus()
print(f'{ name } total salary..')
return salary + bonus
print(getEmployeeSalary('Coding News Today'))

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