Help with Arithmetic Formatter - Only returning one equation

Python
#1

Hello All,

I have been working on the Arithmetic Formatter project and struggling to return all the equations. It seems I have it formatted correctly for it will return with solution when asked but will only return the last equation from the array. I must be missing something obvious. Any thoughts?

def arithmetic_arranger(problems, solutions = False):
  if len(problems) > 5 : 
    return('Error: Too many problems.')
  
  line1 = ""
  line2 = ""
  line3 = ""
  line4 = ""
  arranged_problems = ''
  
  for problem in problems: 
    num1 = problem.split(" ")[0]
    operator = problem.split(" ")[1]
    num2 = problem.split(" ")[2]
    
    if not ((operator == "+") or (operator == "-")):
      return("Error: Operator must be '+' or '-'.")
    if num1.isnumeric() == False :
      return('Error: Numbers must only contain digits.')
    if num2.isnumeric() == False:
      return ('Error: Numbers must only contain digits.')
    if (len(num1) > 4) or (len(num2) > 4) : 
      return ('Error: Numbers cannot be more than four digits.')
    
    solution = ""
    if (operator == "+") : 
      solution = str(int(num1) + int(num2))
    elif (operator == "-") : 
      solution = str(int(num1) - int(num2))
  
    width = max(len(num1), len(num2)) + 2
    top = str(num1).rjust(width)
    bottom = operator + str(num2).rjust(width - 1)
    line = ""
    answer = str(solution).rjust(width)
    for x in range(width) : 
      line += "-"
    
    if problem != problems[-1] : 
      line1 += top + '    '
      line2 += bottom + '    '
      line3 += line + '    '
      line4 += answer + '    '
    else : 
      line1 = top
      line2 = bottom
      line3 = line
      line4 = answer

  if solutions == True : 
    arranged_problems = line1.rstrip() + "\n" + line2.rstrip() + "\n" + line3.rstrip() + "\n" + line4.rstrip()
  else : 
    arranged_problems = line1.rstrip() + "\n" + line2.rstrip() + "\n" + line3.rstrip()
    
  return arranged_problems

Error I am seeing when I run the code:


_______________ test_template[test_five_problems_with_solutions] _______________

arguments = [['32 - 698', '1 - 3801', '45 + 43', '123 + 49', '988 + 40'], True]
expected_output = '   32         1      45      123      988\n- 698    - 3801    + 43    +  49    +  40\n-----    ------    ----    -----    -----\n -666     -3800      88      172     1028'
fail_message = 'Expected solutions to be correctly displayed in output when calling "arithmetic_arranger()" with five arithmetic problems and a second argument of `True`.'

    @pytest.mark.parametrize('arguments,expected_output,fail_message', test_cases)
    def test_template(arguments, expected_output, fail_message):
        actual = arithmetic_arranger(*arguments)
>       assert actual == expected_output, fail_message
E       AssertionError: Expected solutions to be correctly displayed in output when calling "arithmetic_arranger()" with five arithmetic problems and a second argument of `True`.
E       assert '  988\n+  40\n-----\n 1028' == '   32       ... 172     1028'
E         -    32         1      45      123      988
E         - - 698    - 3801    + 43    +  49    +  40
E         - -----    ------    ----    -----    -----
E         -  -666     -3800      88      172     1028
E         +   988
E         + +  40
E         + -----...
E         
E         ...Full output truncated (2 lines hidden), use '-vv' to show

test_module.py:77: AssertionError

Thank you in advance!

#2

This means you are replacing the variable on the left every single iteration. Why not update each line instead and join the lines after the loop?

#4

Thank you! Wow that was simple!
Thank you Again!!

 python main.py
   32      3801      45      123
+ 698    -    2    + 43    +  49
-----    ------    ----    -----
=========================== test session starts ===========================
platform linux -- Python 3.8.12, pytest-6.2.5, py-1.11.0, pluggy-1.0.0
rootdir: /home/runner/boilerplate-arithmetic-formatter-3
collected 10 items                                                        

test_module.py ..........                                           [100%]

=========================== 10 passed in 0.03s ============================

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