BUG a simple "and" and "or"

[Samran]

BPO	41436
Nosy	@tirkarthi, @jameshcorbett
Files	Command Prompt - python test.py 29-Jul-20 9_16_22 PM (2).png: Just a simple bug. I tried updating python and testing still can't get desired result.

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

Show more details

GitHub fields:

assignee = None
closed_at = <Date 2020-07-29.16:58:11.992>
created_at = <Date 2020-07-29.16:30:45.836>
labels = ['3.8', 'type-bug', 'tests', 'invalid']
title = 'BUG a simple "and" and "or"'
updated_at = <Date 2020-07-30.02:55:56.304>
user = 'https://bugs.python.org/Samran'

bugs.python.org fields:

activity = <Date 2020-07-30.02:55:56.304>
actor = 'Samran'
assignee = 'none'
closed = True
closed_date = <Date 2020-07-29.16:58:11.992>
closer = 'xtreak'
components = ['Tests']
creation = <Date 2020-07-29.16:30:45.836>
creator = 'Samran'
dependencies = []
files = ['49347']
hgrepos = []
issue_num = 41436
keywords = []
message_count = 5.0
messages = ['374576', '374577', '374578', '374594', '374595']
nosy_count = 2.0
nosy_names = ['xtreak', 'jameshcorbett', 'Samran']
pr_nums = []
priority = 'normal'
resolution = 'not a bug'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue41436'
versions = ['Python 3.8']

[Samran]

#this is the code

from random import randint

num = randint(1,10)

print(type(num))

print(num)

ch = None                                                                                           #tried changing this tried converting types

guess = 0

print(type(guess))

print("Welcome to guessing game: ")

while ch != 'n' or ch != 'N':                                            #here is the bug this statement is not running. It works with “and”

            while( guess != num):

                                guess = int(input("Enter your guess?  "))

                                if guess == num:

                                                print("You Guessed Congratz")

                ch=input("Enter 'y' to play or 'n' to exit: ")

                if ch=='y' or ch == 'Y':

                                guess= 0

                                num = randint(1,10)

print("Thankyou for playing.")

[jameshcorbett]

I think this would have been a better fit for a StackOverflow issue: https://stackoverflow.com/questions/tagged/python. Also, it's not a compilation error and it doesn't have anything to do with CPython's testing framework.

Anyway, I don't think this is a bug. For a string ch, it is always true that either ch != 'n' or ch != 'N'---no string is equal to both 'N' and 'n'. Therefore your while condition will always be true and the loop will always continue.

As you already noted, your loop will terminate properly if you used `and`. You could also rewrite it as `while ch not in ('n', 'N'):` which I think is clearer.

[tirkarthi]

Below is the formatted program for easier reading. In the while clause you ask for the user to enter n to exit but you check (ch != n or ch != N) so on entering "n" the first condition is false but second clause is true. For "N" it's vice-versa. You want to continue the game as long as ch is not 'n' or "N'. Hence using not(ch == 'n' or ch == 'N') will help in exiting the program. This website is for bugs related to CPython itself. Please refer to stack overflow or other mailing lists in future.

Thanks.

from random import randint

num = randint(1, 10)

print(type(num))
print(num)

ch = None  # tried changing this tried converting types
guess = 0
print(type(guess))
print("Welcome to guessing game: ")


while (
    ch != "n" or ch != "N"
):  # here is the bug this statement is not running. It works with “and”
    while guess != num:
        guess = int(input("Enter your guess?  "))
        if guess == num:
            print("You Guessed Congratz")
            ch = input("Enter 'y' to play or 'n' to exit: ")
            if ch == "y" or ch == "Y":
                guess = 0
                num = randint(1, 10)

print("Thankyou for playing.")

Fixed program :

from random import randint

num = randint(1, 10)

print(type(num))
print(num)

ch = None  # tried changing this tried converting types
guess = 0
print(type(guess))
print("Welcome to guessing game: ")


while not (
    ch == "n" or ch == "N"
):  # Play until the ch is not n or N 
    while guess != num:
        guess = int(input("Enter your guess?  "))
        if guess == num:
            print("You Guessed Congratz")
            ch = input("Enter 'y' to play or 'n' to exit: ")
            if ch == "y" or ch == "Y":
                guess = 0
                num = randint(1, 10)

print("Thankyou for playing.")