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

Posted by Adam Cassano
Adam Cassano
4,702 Points

ive been working on this for the last 2 days; im sure the solution is easy but i guess im not understanding whats wrong.

i also went back in the video and could not find where he used a for loop anywhere. if someone can help me understand this better i would appreciate it.

functions.py 
number_list = list()
total = (num)

def add_list(num):  # add_list([1, 2, 3]) should return 6
  number_list.append(num)
  print("The Total is, {}".format(total))

for num in number_list:
  total  = num + num

# summarize([1, 2, 3]) should return "The sum of [1, 2, 3] is 6."
# Note: both functions will only take *one* argument each.
Silviu Cosma
Silviu Cosma
1,756 Points

Hello Adam.

To pass this challenge we have to create the list:

list = [1, 2, 3]

After you define the function add_list which will take as argument our list:

def add_list(list): return "The total is {}.".format(sum(list)

print add_list(list)

To be able to do the sum all the elements from the list you have to use the sum() method.

There is no need to apply the for loop.

2 Answers

Dan Johnson
Dan Johnson
40,533 Points
Dan Johnson
Dan Johnson
40,533 Points

The challenge is expecting two separate functions: add_list to sum all elements of the list, and summarize, to format a string to display the result.

For add_list you'll want to loop through the list like you did, but to update the total as you go along you'll want to add the current value of total to the current element the loop is on:

def add_list(number_list):
  total = 0

  for number in number_list:
    total = total + number     #This can be shortened to total += number

  return total

For summarize, you'll want to use the string exactly as it is shown in the challenge:

def summarize(number_list):
  return "The sum of {} is {}.".format(number_list, add_list(number_list))

You won't need to create a list or append any data to one, a list will be supplied when your code is being checked.

Kenneth Love
STAFF
Kenneth Love
Treehouse Guest Teacher
Kenneth Love
Kenneth Love
Treehouse Guest Teacher

We do for loops in this video, on the stage previous to the one this code challenge is in.