Getting a confusing TypeError. Mastermind game

Question

I have finished creating the MasterMind game, but I am getting a TypeError that I am not able to debug. It does say what I am doing wrong on the error, but do not know how to fix this. This is my code:

import random
letters = ["A", "B", "C", "D", "E", "F"]
length = 4

def main():
  list_code = create_code(4)
  secret_code = "".join(list_code)

  guess_counter = 0
  guess = ""
  list_guess = ""
  while guess_counter < 10 and guess != secret_code:
    list_guess = get_code()
    guess = "".join(list_guess)
    result = check_code(secret_code, guess)
    guess_counter+= 1
  

  if guess == secret_code:
    print("You win!")
  else:
    print("Sorry, you lost. The corect code was", secret_code)


def create_code(length):
  letters_copy = letters.copy()
  code_word = ""
  for i in range(length):
    letter = random.choice(letters_copy)
    letters_copy.remove(letter)
    code_word = code_word + letter
  code = list(code_word)
  return code

def get_code():
  guess_code = input("Guess the 4 digit code (abcd): ").upper()
  user_code = list(guess_code)
  if len(user_code) != length:
    print("Must enter only 4 letters")
    user_code = get_code()
  for i in guess_code:
    if user_code[i] in letters: 
      continue
    else:
      print("invalid answer, choose between letters a, b, c, d, e, f")
      user_code = guess_code()
      break
  return guess_code


def check_code(secret_code, guess):
  white_counter = 0
  red_counter = 0
  win = False
  for i in guess:
    if guess[i] in secret_code[i]:
      red_counter += 1
      continue
    elif guess[i] in secret_code:
      white_counter += 1
      continue
    else:
      continue
  print("R"*red_counter, "W"*white_counter)
  return white_counter, red_counter


main()

And the error I am getting when I run this program is:

Traceback (most recent call last):
  File "main.py", line 71, in <module>
    main()
  File "main.py", line 13, in main
    list_guess = get_code()
  File "main.py", line 42, in get_code
    if user_code[i] in letters: 
TypeError: list indices must be integers or slices, not str

I don't know what I am doing wrong so any help would be great. Thank you!

Answer 1

At lines 41 and 55, you should be referencing element index and not the element it.

import random
letters = ["A", "B", "C", "D", "E", "F"]
length = 4

def main():
    list_code = create_code(4)
    secret_code = "".join(list_code)

    guess_counter = 0
    guess = ""
    list_guess = ""
    while guess_counter < 10 and guess != secret_code:
        list_guess = get_code()
        guess = "".join(list_guess)
        result = check_code(secret_code, guess)
        guess_counter+= 1


        if guess == secret_code:
            print("You win!")
        else:
            print("Sorry, you lost. The corect code was", secret_code)


 def create_code(length):
     letters_copy = letters.copy()
     code_word = ""
     for i in range(length):
         letter = random.choice(letters_copy)
         letters_copy.remove(letter)
         code_word = code_word + letter
         code = list(code_word)
     return code

def get_code():
    guess_code = input("Guess the 4 digit code (abcd): ").upper()
    user_code = list(guess_code)
    if len(user_code) != length:
        print("Must enter only 4 letters")
        user_code = get_code()
    for i in range(len(guess_code)): #correction here
        if user_code[i] in letters: 
        continue
    else:
        print("invalid answer, choose between letters a, b, c, d, e, f")
        user_code = guess_code()
        break
    return guess_code


def check_code(secret_code, guess):
    white_counter = 0
    red_counter = 0
    win = False
    for i in range(len(guess)): #correction here
        if guess[i] in secret_code[i]:
            red_counter += 1
            continue
        elif guess[i] in secret_code:
            white_counter += 1
            continue
        else:
            continue
        print("R"*red_counter, "W"*white_counter)
        return white_counter, red_counter

main()