Sum a list

Add up every number in a list and return the total. Start a running total at 0, then loop over the list and add each value to it.

This pattern — a running total that grows inside a loop — comes up everywhere in programming.

Write sum_list(xs) that returns the total of all numbers in the list xs. An empty list sums to 0.

def sum_list(xs):
    # add up every number in xs
    return 0

Click Run to see the output here.

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