为什么此代码会产生错误“ int无法下标”？

Question

I have converted the variable to a string, however Python still does not recognise this and says the integer is not subscriptable.

I've already tried viewing other questions with the same 'integer is not subscriptable' problem but none which answer my question specifically.

I have explicity converted the variable to a string the line before the error occurs.

 import random

 num = random.randint(1000, 9999)
 tot_correct = 0
 tot_tries = 0

 while tot_correct != 4:
     tot_correct = 0
     tot_tries += 1
     guess = input("Guess the number: ")
     guess = str(guess)
     #check 1st number
     if guess[0] == num[0]:
         tot_correct += 1

     #check 2nd number
     if guess[1] == num[1]:
         tot_correct += 1

     #check 3rd number
     if guess[2] == num[2]:
         tot_correct += 1

     #check 4th number
     if guess[3] == num[3]:
         tot_correct += 1
     print("You got " + tot_correct + " numbers right.")

print("You have guessed the number correctly! It took you " + tot_tries + "   tries.")

I expected the string to become a string array, (but it still does not, and returns the same error) and then identify whether or not the individual number matches the one already

Answer 1

Your code isn't doing what you think it is. Right now you are inputting a number, converting it to a string and comparing the first character of that guess string to the first index of the number num[0] which isnt indexable.

edit: Your code is doing a number of things wrong actually. One huge problem you have is you are setting tot_correct = 0 inside of your while loop which means it'll run forever and never finish.

But stepping back I think you are making this problem too complicated. Let's talk about the pseudocode for what I believe you are trying to do.

num_guessed = 0
number_to_guess = 4
total_guesses = 0
while num_guessed < number_to_guess:
    # each pass we reset their guess to 0 and get a new random number
    guess = 0
    # get a new random number here
    while guess != random:
        # have a user guess the number here
        total_guesses += 1 # we can increment their total guesses here too
        # it would be a good idea to tell them if their guess is higher or lower
        # when they guess it right it will end the loop

    num_guessed += 1

# down here we can tell them game over or whatever you want

The code should at least give you an idea of how to approach the problem without solving it for you.

Answer 2

I respectfully disagree with the previous comment. It will be possible for the loop to end. I understand why you are setting tot_correct to 0 at the start of each loop. Because tot_correct is incremented up to 4 times, it is possible for tot_correct == 4 to be true.

Edit: The poster is trying to count the correct number of digits provided. So if the number to guess is '1234' and the user inputs '1564', the poster wants the code to return '2' to indicate that the '1' and '4' were correct numbers. It's like the game mastermind, where a player has to guess the correct colors and orientation of the colors. However, this code will not inform the user if a correct number is added in an incorrect position, just if the correct number is in the correct position.

However, he is correct that your error lies in your access of num[<index>] . num is an integer so you cannot index into it, hence 'integer is not subscriptable.' num needs to be a string in order to index the characters.

Edit: guess was already a string without the call to str() because the return from input() is a string

Some things to consider: Do you want your user to know they need a 4 digit number? What if there are whitespaces added? Currently your code does not remove whitespace. If you are looking for '6543' as the magic number and I enter ' 6543' your solution would not recognize my answer as correct.