Scientific Computing with Python Projects - Arithmetic Formatter

Tell us what’s happening:
Describe your issue in detail here.

Your code so far

import re
def arithmetic_arranger(problems, solve = False):

  if (len(problems) > 5):
    return "Error: Too many problems"

  first = ""
  second = ""
  lines = ""
  sumx = ""
  string = ""
  for problem in problems:
    if (re.search("[^s0-9.+-]", problem)):
      if (re.search("[/]", problem) or re.search("[*]", problem)):
        return "Error: Operator must be '+' or '-'."
      return "Error: Numbers must be only contain digits."

    firstNumber = problem.split("") [0]
    operator = problem.split("") [1]
    secondNumber = problem.split("") [2]

    if (len(firstNumber) >= 5 or len(secondNumber) >= 5):
      return "Error: Numbers cannot be more than four digits."

    sum = ""
    if (operator == "+"):
      sum = str(int(firstNumber) + int(secondNumber))
    elif (operator == ""):
      sum = str(int(firstNumber) - int(secondNumber))

    length = max(len(firstNumber), len(secondNumber)) + 2
    top = str(firstNumber).rjust(length)
    bottom = operator + str(secondNumber).rjust(length - 1)
    line = ""
    res = str(sum).rjust(length)
    for s in range (length):
      line += "-"

    if problem != problems[-1]:
      first += top + ' '
      second += bottom + ' '
      lines += line + ' '
      sumx += res + ' '

    else:
      first += top
      second += bottom
      lines += line
      sumx += res

  if solve:
    string = first + "\n" + second + "\n" + lines + "\n" + sumx
  else:
    string = first + "\n" + second + "\n" + lines
  return string

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Challenge: Scientific Computing with Python Projects - Arithmetic Formatter

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