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Python Python Basics (Retired) Putting the "Fun" Back in "Function" Functions

Michael Rawlinson
Michael Rawlinson
1,507 Points

Adding a list - python

How would I add all the numbers in a list, within a function

functions.py
# add_list([1, 2, 3]) should return 6
def add_list(lists):
  for numb in lists:
    numb[0] + numb[1] + numb[2]
# summarize([1, 2, 3]) should return "The sum of [1, 2, 3] is 6."
# Note: both functions will only take *one* argument each.

1 Answer

Chris Freeman
MOD
Chris Freeman
Treehouse Moderator 68,064 Points

Hi Michael, you're very close. This missing part is to accumulate the total as the for loop runs:

def add_list(lists):
    # initialize total to 0
    total = 0
    for numb in lists:
        # Add numb to total
        total += numb
    # Remember to return a value from the function
    return total

Reminder: total += numb is equivalent to total = total + numb