Python Functools Partial

“A Python standard framework is called Functools. It enables users to increase the performance of the methods or callable elements without having to rewrite these functions. The objective of functools is to increase the efficiency of structured programming. Interacting with high-order processes is made simple by using this. The method functools partial accepts a component as a parameter as well as some pre-filled parameters to provide a specific framework that has been effective.”

Python Partial() Method

A method may occasionally require more than one argument. A Python partial method will be defined if we frequently provide a similar argument to a method. Some of the arguments in the partial method are constants. It’s helpful for renaming an existing method to something more relevant.

Syntax of partial() Method

To construct a partial method, utilize the partial() technique of the functools package in Python. Higher-level procedures are handled by the functools library. The syntax for the partial() method is:

The parameters for the partial method are a method and a preassigned integer for one of its arguments. Using defined positional and keyword parameters, it constructs a partial method that operates as though it were executing “func.” Only a couple of the parameters needed to invoke the actual method could have been sent. The *args and **kwargs contain the additional parameters.

Example no 1

We can specify a specific number of parameters in a method and create a new method by employing partial functionalities.

from functools import partial

def f(a1, b1, c1, x1):

    return 1000*a1 + 100*b1 + 10*c1 + x1

g = partial(f, 31, 61, 9)


We start the program by integrating the header file partially from the module “functools”. Then we define a normal function “f” by calling the def() method. This method holds four values as its arguments. This functionality returns different values in which we multiplied 1000 by the first value, 100 by the second value, and 10 by the third value.

Now we utilize a partial() method that calls a normal function with three other numerals. These values are stored in a variable “g”. At the end of the program, we will employ the print() function to display the resultant value of g.

In this illustration, we’ve pre-filled the method by using the values of variables which include a1, b1, and c1. Additionally, g() only requires one parameter.

Example no 2

We may reuse the program by using partial methods to create particular methodologies from basic functionalities. Bind in C++ Programming language is comparable to this capability.

from functools import *

def add(a1, b1, c1):

    return 1000 * a1 + 110 * b1 + c1

add1_part = partial(add, c1 = 22, b1 = 81)


First of all, we will import ‘*’ from the functools framework. Then we define the function add(). We pass three elements as the parameters to this function. To return the result by using this function, we do multiplication. The first value, “a1” will be multiplied by 1000, and the second element, “b1” will be multiplied by 110. In the next step, we utilize the partial() method.

Here we specify the values of attribute “c1” as well as attribute “b1”. We declare a variable “add1_part” to store the values obtained by using the partial() function. To terminate the code, we have been calling the function add1_part(). We provide the values of this function as the argument to the print() function.

Example no 3

A method having a single argument could be reduced to a method with fewer arguments and definite values while using partial expressions.

from functools import partial

def multiply(a, b):

        return a * b

db = partial(multiply, 22)


At the beginning of the program, we have to import the required package “partial” from the “functools”. The function multiply() is defined subsequently. The parameters we supply to this function include two values. We multiply the result before returning it using this procedure. The second element, “b,” will be multiplied by the first value, “a.” The partial() function is being used in the following step.

Here, we’ll supply the multiplied value and 22 to this function as parameters. We create the variable “db” to hold the results of the partial() method. We have been calling the function db() to end the program. We give the print() method the values of the db() function as a parameter.

Example no 4

The multiply() method’s parameters are reduced by the double() method. The multiply method’s second parameter is paused by the double() procedure, creating a new mechanism by a more explicit signature. The double() method is referred to as a partial method in Python. Because we would occasionally construct partial methods, Python gives users access to the partial method from the functools framework to make the implementation of partial methods simpler.

The new partial attribute that the partial method provides can be callable. Python executes the method containing the positional parameters and keyword parameters if we invoke the partial instance. The partial functionality would be utilized to construct the double() method from the multiply() method, as shown in the illustration that follows.

from functools import partial

def multiply(x, y):

    return x*y

double = partial(multiply, y=20)

result_1 = double(8)


We will include the partial utility from the functools library at the commencement of the program. After this, the multiply() function can be defined. Two parameters are given in this method. The partial method is therefore called to create a partial item, which is subsequently allocated to the double attribute.

Python executes the multiply() method with a default value of 20 as we invoke the double() method. Python provides additional parameters to the args attribute for a partial element if we provide them. It expands and modifies the keyword parameters if we supply them to a partial instance.


The use of the Python functools partial has been addressed in this guide. By using the partial method from the functools framework, we may construct partial methods in Python. We have been using a partial method from the functools package in different instances.  The multiply method’s intricacy is alleviated by the use of the double method. Whenever we want to modify a method’s signature by limiting the number of parameters, then we utilize partial methods.

About the author

Kalsoom Bibi

Hello, I am a freelance writer and usually write for Linux and other technology related content