I need my display variable to be updated. Now it is resetting to null list

while test_list != display:
 display=[] 
 guess = input("Guess a letter: ").lower()
 for letter in chosen_word:
  
  if letter == guess:
      display+=[letter]  
  else:
      display+=["_"] 
 print(display)

Display variable is resetting to null 

This code is part of hangman game. So the letter inputted by the user is checked for match with the word and it prints out a list with underscores and along with the correct guess in each position.
However, when i input another word the display variable is resetting to null list. I want it to be updated by the code.

Thanks in Advance 🙂

>Solution :

that is because you are creating a new display list on every iteration of your loop without saving your old list somewhere.

a solution is to save your old list in a variable, let’s call it old_display, then we can check if that letter was already picked.

old_display = []
while test_list != display:
    display = []
    guess = input("Guess a letter: ").lower()
    for letter in chosen_word:

        if letter == guess:
            display += [letter]
        elif letter in old_display:  # check what was picked before
            display += [letter]
        else:
            display += ["_"]
    old_display = display  # update the old list to be the new list
    print(old_display)