Everybody loves to write reusable code, right? Then partial function is a cool thing to learn. Partial functions allows us to derive a function with x parameters to a function with fewer parameters and constant values set for the more limited function.
We can write partial functional application in python through functools library. Below is a simple example of partial function from the functools library with the add function from the operator library.
>>> from functools import * >>> from operator import * >>> add(1,2) 3 >>> add1 = partial(add, 4) >>> add1(6) 10 >>> add1(10) 14
Partial is a higher order function which takes a function as input (like map and filter) but it also returns a function that can be used in the same way as any other function in your program.
>>> list(map (add1, [1, 2, 3, 4, 5])) [5, 6, 7, 8, 9] >>> seven = partial(add1, 3) >>> seven() 7
We can also use partial on object methods, for e.g. to generate a list of default strings −
>>> str1 = "Hello, Python"
>>> helloStr = partial(str1.replace, "Python")
>>> helloStr("Tutorialspoint")
'Hello, Tutorialspoint'
>>> helloStr("Java")
'Hello, Java'Partial function application is a very useful tools especially where you need to apply a range of different input to a single object or need to bind one of the arguments to a function to be constant.
Python function helps you to write your code easily and easier to maintain.
