Writing a function that alternates plus and minus signs between list indices

Question

In a homework set I\'m working on, I\'ve come across the following question, which I am having trouble answering in a Python-3 function:

\"Write a fun

Answer 1

def alternate(l):
  return sum(l[::2]) - sum(l[1::2])

Take the sum of all the even indexed elements and subtract the sum of all the odd indexed elements. Empty lists sum to 0 so it coincidently handles lists of length 0 or 1 without code specifically for those cases.

References:

• list slice examples
• sum()