How to create higher-order functions in Python?
In Python, a function that takes another function as a parameter or returns a function as output is called a higher-order function. Let's take a look at its features -
This function can be stored in a variable.
This function can be passed as a parameter to another function.
Higher-order functions can be stored in lists, hash tables, etc.
Functions can be returned from functions.
Let’s look at some examples −
Function as Object
The Chinese translation ofExample
is:Example
In this example, these functions are treated as objects. Here, the function demo() is assigned to a variable -
# Creating a function
def demo(mystr):
return mystr.swapcase() # swapping the case
print(demo('Thisisit!'))
sample = demo
print(sample('Hello'))
Output
tHISISIT! hELLO
Passing functions as parameters
The Chinese translation ofExample
is:Example
Passed as a parameter in this function. demo3() The function calls the demo() and demo2() functions as parameters.
def demo(text):
return text.swapcase()
def demo2(text):
return text.capitalize()
def demo3(func):
res = func("This is it!") # Function passed as an argument
print (res)
# Calling
demo3(demo)
demo3(demo2)
Output
tHIS IS IT! This is it!
Now, let’s discuss decorators. We can use decorators as higher order functions.
Decorators in Python
The Chinese translation ofExample
is:Example
In a decorator, a function is passed as a parameter to another function and then called in the wrapping function. Let’s look at a quick example −
@mydecorator
def hello_decorator():
print("This is sample text.")
The above can also be written as -
def demo_decorator():
print("This is sample text.")
hello_decorator = mydecorator (demo_decorator)
Decorator example
The Chinese translation ofExample
is:Example
In this example, we will work with decorators as higher-order functions -
def demoFunc(x,y):
print("Sum = ",x+y)
# outer function
def outerFunc(sample):
def innerFunc(x,y): # inner function
return sample(x,y)
return innerFunc
# calling
demoFunc2 = outerFunc(demoFunc)
demoFunc2(10, 20)
Output
Sum = 30The Chinese translation of
Example
is:Example
def demoFunc(x,y):
print("Sum = ",x+y)
# outer function
def outerFunc(sample):
def innerFunc(x,y): # inner function
return sample(x,y)
return innerFunc
# calling
demoFunc2 = outerFunc(demoFunc)
demoFunc2(10, 20)
Output
Sum = 30
Apply syntax decorator
The Chinese translation ofExample
is:Example
The above example can be simplified using a decorator with @symbol. The application of decorators can be simplified by placing the @ symbol before the function we want to decorate -
# outer function
def outerFunc(sample):
def innerFunc(x,y): # inner function
return sample(x,y)
return innerFunc
@outerFunc
def demoFunc(x,y):
print("Sum = ",x+y)
demoFunc(10,20)
Output
Sum = 30
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