While loop goes on forever despite condition being met

Question

My while loop is supposed to end once each letter in display is not an underscore.

However despite display updating to remove all underscores. The loop keeps going on, and I can't figure out why.

import random
word_list = ["aardvark", "baboon", "camel"]
chosen_word = random.choice(word_list)
word_length = len(chosen_word)


print(f'Pssst, the solution is {chosen_word}.')

display = []
for _ in range(word_length):
    display += "_"


guess = input("Guess a letter: ").lower()

def check_letter():
  for position in range(word_length):
      letter = chosen_word[position]
      if letter == guess:
          display[position] = letter
  print(display)

check_letter()

for item in display:
  while item == "_":
    guess = input("Guess a letter: ").lower()
    check_letter()

print("You've Won")
  

Answer 1

item is a copy of your display element. This may be what you want

for i in range(word_length):
  while display[i] == "_":
    guess = input("Guess a letter: ").lower()
    check_letter()

Answer 2

import random
word_list = ["aardvark", "baboon", "camel"]
chosen_word = random.choice(word_list)
word_length = len(chosen_word)
display = []

print(f'Pssst, the solution is {chosen_word}.')

display = []
for _ in range(word_length):
    display += "_"


guess = input("Guess a letter: ").lower()

def check_letter(display):
  for position in range(word_length):
      letter = chosen_word[position]
      if letter == guess:
          display[position] = letter
  print(display)

check_letter(display)

for item in display:
  while item == "_":
    guess = input("Guess a letter: ").lower()
    check_letter(display)
    if (''.join([str(elem) for elem in display]) == chosen_word) :
        break


print("You've Won")

Answer 3

I played with your code for much longer than I thought I would. The problem is subtle.

The issue with your code is that item never changes it's value (despite the for loop). And that's why the problem is subtle - the for loop ( for item in display: ) only iterates once because the while loop it contains is endless. The while loop is endless is because nothing in the while loop changes the value of item .

All that said, I can see why you are asking here at SO. Here's a bit of code that eliminates the for loop for just a while loop. I've eliminated the item variable - it doesn't change anyway. Rather, the condition that keeps us in the loop is there is still an underscore in the display variable.

import random
word_list = ["aardvark", "baboon", "camel"]
chosen_word = random.choice(word_list)
word_length = len(chosen_word)


print(f'Pssst, the solution is {chosen_word}.')

display = []
for _ in range(word_length):
    display += "_"


guess = input("Guess a letter: ").lower()

def check_letter():
  for position in range(word_length):
      letter = chosen_word[position]
      if letter == guess:
          display[position] = letter
  print(display)

check_letter()

while '_' in display:
    guess = input("Guess a letter: ").lower()
    check_letter()

print("You've Won")

Answer 4

And another solution;

from calendar import c
import random
word_list = ["aardvark", "baboon", "camel"]
chosen_word = random.choice(word_list)
word_length = len(chosen_word)
guessed_word = []


print(f'Pssst, the solution is {chosen_word}.')

display = []
for _ in range(word_length):
    display += "_"


guess = input("Guess a letter: ").lower()

def check_letter():
  for position in range(word_length):
      letter = chosen_word[position]
      if letter == guess:
          display[position] = letter
          # append the letter to the guessed_word list at the correct position
          guessed_word.insert(position, letter)
  print(display)

check_letter()

for item in display:
    
    while item == "_":
        gw = ''.join(guessed_word)
        cw = ''.join(chosen_word)
        if gw == cw:
            print("You win")
            break
        else:    
            guess = input("Guess a letter: ").lower()
            if guess in display:
                print(f"You've already guessed {guess}")
            else:
                check_letter()