ex_10_03.py

#!/usr/bin/python
#AUTHOR: alexxa
#DATE: 28.12.2013
#SOURCE: Think Python: How to Think Like a Computer Scientist by Allen B. Downey
# http://www.greenteapress.com/thinkpython/html/index.html
#PURPOSE: Chapter 10. Lists
# Exercise 10.3

# Write a function that takes a list of numbers and returns 
# the cumulative sum; that is, a new list where the ith element 
# is the sum of the first i + 1 elements from the original list.
# For example, the cumulative sum of [1, 2, 3] is [1, 3, 6].

def nested_sum(listik):
    total = 0
    res = []
    for i in listik:
        total += i
        res.append(total)
    return res

print(nested_sum([1,2,3]))
print(nested_sum([]))
print(nested_sum([-1,1,2,0]))

#END