CODEWITHSUNDEEP
pythonpython-3.x
PaolaB
PaolaB

Reputation: 13

Appending sum of last two integers of a list to that same list

Edit: I should add that the focus for this problem is on the use of 'side effects' in a function.

I am submitting my code on my computing course on Coursera. I think I must be missing something super obvious. When I submit my code I get the following error:

#TEST 5#
append_fibonacci(args) returned None ** ERROR ** side effect from: [-5, 8, 1] to: [-5, 8, 1] * EXPECTED: * [-5, 8, 3]
inputs:

outputs:

I mostly just don't understand what the feedback is telling me. I'm a bit of a newbie, having just started Python this month. Thank you for your help!

The following is my code:

def append_fibonacci(integer_list):
  # Modify the argument list of integers by
  # appending a new integer that is the sum
  # of the last two integers in the list.
  # If the list has fewer than two elements
  # add the int object 1 to the list.

  if len(integer_list) > 2:
    sum_last_two = ((integer_list[-1]) + (integer_list[-2]))
    integer_list.append(sum_last_two)
  else:
    integer_list.append(1)

def main():
  # Call the append_fibonacci function on this
  # list: [3, 5, 8] and output the result object

  number_list = [3, 5, 8]
  append_fibonacci(number_list)
  print(number_list)

main()

Upvotes: 0

Views: 595

Answers (1)

Barmar
Barmar

Reputation: 780724

The error message you got is saying that the updated list should be [-5, 8, 3] but you're setting it to [-5, 8, 1]

This is because your function doesn't work correctly if the list has exactly 2 elements. It should add the two elements and append the sum (-5 + 8 = 3), but it will instead just append 1.

if len(integer_list) > 2:

should be:

if len(integer_list) >= 2:

Upvotes: 1

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