初学者：虽然循环无法正常运行，但语法错误，未显示任何内容

Question

I am working through some Looping exercises, While statements in particular. Here are the instructions:

2.2) Modify the program so that it asks users whether they want to guess again each time. Use two variables, number for the number and answer for the answer to the question whether they want to continue guessing. The program stops if the user guesses the correct number or answers "no". (In other words, the program continues as long as a user has not answered "no" and has not guessed the correct number.)

Here is my code:

#!usr/bin/env python
#
#While statement

number = 24

while number != 24:
    answer = raw_input("Guess my lucky number! Do you want to keep guessing?")

    if number == 24:
       print "You got it! That is great!"

    elif answer == "no":
       print "Thank you for playing."

    else:
       print "That is not the right answer! Try again."

When I run the module in IDLE, the end quote of That is great!" - becomes red and says invalid syntax. In terminal if I run $ python while.py nothing loads. I've tried writing this as Python 3 functions with print("") but it still does not run.

Thanks to anyone who can help with this.

Answer 1

The while-cycle is never entered because the condition number != 24 never holds. This is why there is no output.

Answer 2

Your loop never executes because you state that number = 24, and then right after, your while loop will only start if number != 24.

In addition, raw_input will yield a string, not an int so either ask for "24" or cast the raw_input to an int.

It also seems that you don't actually give the user a chance to guess the number at all; you only ask the user if s/he wants to keep playing.

You might want to do something like this:

number = 24
answer = ""
while answer != str(number):
    answer = raw_input("Guess my lucky number, or type 'no' to quit.")
    if answer == "no":
        print "Okay, see you later"
        break
    elif answer != str(number):
        print "wrong number"

if answer == str(number):
    print "you got it right"

Answer 3

Here's the syntax issues:

answer = ""
while answer != "24":
    answer = raw_input("Guess my lucky number! Do you want to keep guessing?")
    if answer == "24":
        # You can fill in the rest ...

Answer 4

Well, I don't want to straight out solve it for you, but take a look at your conditional in the while loop. Think about what happens, line-by-line, when you run it, particularly in the "number" variable.

Answer 5

The other answers are touching on the problem but there are more...

Yes you really should be checking the answer variable in your loop instead of the number variable, but also keep in mind that raw_input is going to give you a string. So you will not get an int 24, you will get a string "24". The idea here is to take the answer variable from raw_input and check that variable against both your number and the value "no"

number = "24"