Learn Python – Python High Order Function- Basic and advance

As we ought to be conscious of the simple idea of Python functions, we ought to go forward with some advanced standards related to Python functions. In this tutorial, we are going to talk about the vital components of High order features in Python, like what high order functions are, how we can outline them in Python, how we can use them in Python and what the houses of high order features are.

Prerequisites:

To examine about high order features in Python, we ought to have primary expertise of the following concepts:

Python functions

Parameters

Python objects

Python decorators

First, let’s begin with the first thing, i.e., High order functions, and recognize a primary about them.

High order functions

A feature that is having every other characteristic as an argument or a feature that returns every other function as a return in the output is referred to as the High order function. High order features operate with different features given in the program.

A fact about the High order function is that a high order function is applicable to each functions as well as to the strategies that take a characteristic as their parameter or return a function as the result of them. In Python, this concept of high-order features is supported with every aspect.

Properties of High order functions in Python

Now, in this section, we will talk about some of the necessary homes of high order features that are applicable in Python as well.

In high order function, we can store a function inside a variable.

In high order function, a function can act as an instant of an object type.

In high order function, we can return a function as a result of another function.

In high order function, we can pass a function as a parameter or argument inside another function.

We can store Python high order functions in data structures format such as lists, hash tables, etc.

High order functions in Python

Now, in this section, we will speak mainly about the Python excessive order features and how we can outline them. We will talk about the methods and potential by which we will outline and use high order features in our Python program.

Following are the approaches to outline High order features in a Python code that we are going to discuss in this tutorial.

Using functions as objects in High order function
Returning function as a result in high order function
Functions as a parameter for another function
Decorators as high order function

Now, we will talk about every of the above-given techniques in element and research about their implementation as excessive order functions in a Python program.

Method 1: Using functions as objects in High order function

In Python, we can even assign a given function to a variable also. This venture of function into variable will not name the genuine function, alternatively of it will create a reference to the characteristic that is created. Thus, it makes this challenge of assigning a feature as a variable object will create a excessive order feature in the program.

Look at the following instance software to learn the implementation of technique we discussed above:

Example –

# a default function to take another function parameter  
def spell(text):  
    # Making text in upper  
    return text.upper()   
# Taking text as user input  
text = input("Enter a text to print it in uppercase and double: ")  
# Spell function with text  
print(spell(text))   
# Assigning variable with the default function  
scream = spell  
# Scream with text variable  
print(scream(text))  

Output:

Enter a text to print it in uppercase and double: JavaTPoint
JAVATPOINT
JAVATPOINT

Method 2: Functions as a parameter for every other function

Basically, Python features are like Python objects, and consequently we can use Python functions to bypass them as an argument internal any other function, and that will create a high order characteristic in the program.

Look at the following software to recognize the implementation of above-given method:

Example –

# Default function for making text uppercase  
def scream(word):   
    return word.upper()   
# Default function for making text lowercase  
def spell(word):   
    return word.lower()   
# A third function that work as a high order function  
def speak(funct):   
    # Storing the function in a variable in high order function   
    speaking = funct("Hello Python Developers! You are welcomed to JavaTpoint")   
    print(speaking)    
# Printing text in uppercase  
speak(scream)  
# Printing text in lowercase  
speak(spell)  

Output:

HELLO PYTHON DEVELOPERS! YOU ARE WELCOMED TO JAVATPOINT
hello python developers! you are welcomed to javatpoint

Method 3: Returning characteristic as a result in high order function

We can additionally return a feature as the result of some other characteristic as an object, and that makes the function a excessive order function.

Look at the following example software to examine the implementation of technique we mentioned above:

Example –

# A default function for addition  
def Adding(a):  
    # Nested function with second number   
    def Addition(b):   
            return a + b # addition of two numbers  
    return Addition # Result  
  
# Taking both number variable as user input  
a = int(input("Enter First Number: "))  
b = int(input("Enter Second Number: "))  
# Assigning nested adding function to a variable  
AddVariable = Adding(a)  
# Using variable as high order function  
Result = AddVariable(b)  
# Printing result  
print("Sum of Two numbers given by you is: ", Result)  

Output:

Enter First Number: 24
Enter Second Number: 26
Sum of Two numbers given by you is:  50

Method 4: Decorators as high order function

We can use decorators as the excessive order function as the most usually used excessive order characteristic in Python. Decorators in Python allow us to modify the behavior of methods or functions we described in the program, and it additionally permits us to wrap a function inner every other feature to prolong the behavior of wrapped or father or mother function. We can even wrap a characteristic inside every other function besides even completely enhancing the mum or dad function.

In Python decorators, a function is taken as an argument for the different function, and then these decorators are known as internal the wrapped function. Look at the following exemplar syntax for a decorator defined in a Python program.

Syntax

# Using a decorator  
@JTP_Decorator  
def Python_Decorator():   
    .  
    .  

The above syntax for the decorator is equivalent to the following Python code for a high order function.

# Using Python default function as Python decorators  
def Python_Decorator():   
    .  
    .  
Python_Decorator = @JTP_Decorator(Python_Decorator)  

We have referred @JTP_Decorator as a callable function internal the default Python_Decorator() characteristic in the above-given code. We will have to add just some greater code in this structure, and we will get the output as the wrapper function.

Look at the following software to apprehend the implementation of above given method:

Example –

# Using default function as Python decorators  
def Python_Decorator(funct):  
       # Inner nested function  
       def inner():   
              print("This line of code will be printed before the execution of high order function")  
              funct()   
              print("This line of code will be printed after the execution of high order function")  
       return inner   
# A default function as decorator  
def JTP_Decorator():   
    print("This line of code will be printed inside the execution of high order function")  
JTP_Decorator = Python_Decorator(JTP_Decorator) # Python decorator as high order function   
# Python decorator calling out as high order function   
JTP_Decorator()  

Output:

This line of code will be printed before the execution of high order function
This line of code will be printed inside the execution of high order function
This line of code will be printed after the execution of high order function

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