Using map to sum the elements of list

Question

I was wondering if map can be used at all to sum the elements of a list.

assume a = [1, 2, 3, 4]

list(map(sum, a)) will give an error that int object is not iterable because list wants iterables.

map(sum, a) is a valid statement but given the object, I do not see an easy way to dereference it.

[map(sum, a)] will return an object inside the list

this answer states that it should be easy. What am I missing here?

Answer 1

map applies a function to every element in the list. Instead, you can use reduce:

a = [1, 2, 3, 4]
sum_a = reduce(lambda x, y:x+y, a)

In this case, purely sum can be used, however, to be more functional, reduce is a better option.

Or, in Python3:

from functools import reduce
a = [1, 2, 3, 4]
sum_a = reduce(lambda x, y:x+y, a)