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

Why is this not working? it says I am not returning a string total=0 for x in the_list:

def add_list(the_list): total=0 for x in the_list: total=total+x

return total

def summarize(a_list): add_list(a_list) string_list=[] for number in a_list: string_list.append = str(number)

complete = "The sum of {} is {}.".format(string_list, total) return complete

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

  return total

def summarize(a_list):
  add_list(a_list)
  string_list=[]
  for number in a_list:
    string_list.append = str(number)

  complete = "The sum of {} is {}.".format(string_list, total)
  return complete

2 Answers

You're using total to format your string, but you have no access to it. When you call add_list() in your summarize() function you're not assigning the value to any variables. Also, looping through the function creating a new list of strings is not what they want, but instead the original list.

Hey Brenda!

Just to expand on and clarify what Cory has said: Variable names only exist for the duration of the function that they live in. So, when you are referencing total in task 2 of the challenge, Python has no idea what that is because you haven't defined any variable named total within summarize() and you can't access the variable total within add_list() (at least, not in the way you're trying to do so here.)

What you can do, however, is create a new variable (also named total if you want, or anything else) within summarize() and then send the list that is passed into summarize() (which you've named a_list) over to add_list() and assign it to total. In other words, something like this: total = add_list(a_list) Or, you could just skip the variable assignment altogether and call the add_list(a_list) function from within your .format() call.

Another thing to note is that this part:

  string_list=[]
  for number in a_list:
    string_list.append = str(number)

is totally unnecessary. The list (which you've named a_list in this case) is already being passed in as a list of numbers; there is no need to reassign all of the list elements to a new list. You can just use a_list directly, again by sticking it directly into the .format() call, if you wanted.

I hope this helps! Please mark this as the Best Answer if it was most helpful.

Thanks! and Be Well, Graham