Foundations Updated 2026-09 View as Markdown

Partial functions

You can create partial functions in python by using the partial function from the functools library.

You can create partial functions in python by using the partial function from the functools library.

Partial functions allow one to derive a function with x parameters to a function with fewer parameters and fixed values set for the more limited function.

Import required:

from functools import partial

This code will return 8.

from functools import partial

def multiply(x,y):
        return x * y

# create a new function that multiplies by 2
dbl = partial(multiply,2)
print(dbl(4))

An important note: the default values will start replacing variables from the left. The 2 will replace x. y will equal 4 when dbl(4) is called. It does not make a difference in this example, but it does in the example below.

from functools import partial
def func(u,v,w,x):
    return u*4 + v*3 + w*2 + x

p = partial(func,5,6,7)
print(p(8))