Python programming functional vs. imperative code

Question

So I'm currently in a class learning about the 3 major programming paradigms. I know that python uses both the functional and imperative paradigms. I was looking for a short sample code in python of each of these paradigms to better understand this before my exam tomorrow. Thank you!

Answer 1

Given L = [1, 2, 3, 4, 5] we can compute the sum in two ways.

Imperative:

sum = 0
for x in L:
    sum += x

Functional (local function):

def add(x, y):
    return x + y
sum = reduce(add, L)

Functional (lambda expression):

sum = reduce(lambda x, y: x + y, L)

(Of course, the built in sum function would effectively do the same thing as either of these.)