List comprehension for running total

Question

I want to get a running total from a list of numbers.

For demo purposes, I start with a sequential list of numbers using range

a = range         


        

Answer 1

This can be implemented in 2 lines in Python.

Using a default parameter eliminates the need to maintain an aux variable outside, and then we just do a map to the list.

def accumulate(x, l=[0]): l[0] += x; return l[0];
map(accumulate, range(20))