Why does my inner loop never finish in my number guessing game?

Question

When I try to guess the randomly generated number, the correct guess is never correct, and therefore the inner loop never finishes. I have tried debugging with print statements.

from random import randint

print('Welcome to the Number Guessing Game (Numbers 1 - 1000).')

while True:
    tries = 0
    random_num = randint(1, 10)
    print(random_num)
    guess = input('guess my number, human: ')

    while random_num is not guess:
        guess = input('Try again: ')
        print(guess)
        tries += 1

    print('Correct!' + ' It took you' + str(tries) + ' tries.')

You have to convert the input to type `int`. 15 and "15" are *not* equal. — Prune, Mar 30 '18 at 18:17
@Prune Should I answer my question with your answer or delete this question now? — Armend Veseli, Mar 30 '18 at 18:19
I suggest deletion. Both that and the "is not" problem are already covered quite well in both documentation and earlier questions. — Prune, Mar 30 '18 at 18:37

score 1 · Accepted Answer · answered Mar 30 '18 at 18:33

First of all, you have to convert the guess variable to an integer. Input simply returns strings and a string can't be equal to an integer.

The second problem with your programme is that is and is not keywords check, whether two "variables" (in Python, variables are just references to an object) are/aren't pointing to the same object.

This might not be your case even if your guess was correct (even though they can have the same value they are different objects). Sometimes this is not a problem since Python will point both "variables" to the same object for efficiency. But you can't be sure, can you!

Check this: Why does comparing strings in Python using either '==' or 'is' sometimes produce a different result?

Anyways, it's better to use the == and != operator in similar cases and the second problem will disappear.

score 1 · Answer 2 · answered Mar 30 '18 at 18:55

1

Type error...

Add more debug code for the answer

print('random_num',random_num, type(random_num))
print('guess', guess, type(guess))

Output

Welcome to the Number Guessing Game (Numbers 1 - 1000).
random_num 2 <class 'int'>
guess my number, human: 2
guess 2 <class 'str'>

Fix:

while random_num is not int(guess):

answered Mar 30 '18 at 18:55

user8241626

77
5

The `is` will only work for numers in the range [-5, 256]. Python only creates one copy in memory of those numbers which is why `is` works there. For numbers outside this range, `is` will return False. Try `x=300; print(x is 300)`. This outputs False. – SyntaxVoid May 22 '19 at 16:23

Why does my inner loop never finish in my number guessing game?

2 Answers2