Function restriction by fixing an argument

Question

How should I make function with lesser dimensionality than the original one by fixing an argument of it:

For example I want to make successor function out of sum function as follows:

def add(x, y):
    return x + y

Now I am looking for something like this:

g = f(~, 1) which would be the successor function, i.e. g(x) = x+1.

Answer 1

You can write your own function:

def g(y):
    return f(2, y)

Or more concisely:

g = lambda y: f(2, y)

There's also functools.partial:

import functools

def f(x, y):
    return x + y

g = functools.partial(f, 2)

You can then call it as before:

>>> g(3)
5