检查给定的字符串是否是 Python 中的回文字符串

import re
Continue = 1
Quit = 2
def main():
    choice = 0
    while choice != Quit:
        # Display the menu.
        display_menu()
        # Constant to assume string is Palindrome
        is_palindrome = True
        # Get the user's choice.
        choice = int(input('\nEnter your choice: '))
        # Perform the selected action.
        if choice == Continue:
            line = input("\nEnter a string: ")
            str_lower = re.sub("[^a-z0-9]", "", line.lower())
            for i in range(0, len(str_lower)//2):
                if str_lower[i] != str_lower[len(str_lower) - i - 1]:
                    is_palindrome = False
            if is_palindrome:
                print(line, "is a palindrome")
            else:
                print(line, "is not a palindrome")
        else:
            print('Thank You.')
def display_menu():
    print('\n*******MENU*******')
    print('1) Continue')
    print('2) Quit')
main()

Output:

*******MENU*******
1) Continue
2) Quit
Enter your choice: 1
Enter a string: A dog! A panic in a pagoda!
A dog! A panic in a pagoda! is a palindrome
*******MENU*******
1) Continue
2) Quit
Enter your choice: 1
Enter a string: Civic
Civic is a palindrome
*******MENU*******
1) Continue
2) Quit
Enter your choice: 1
Enter a string: Python vs Java
Python vs Java is not a palindrome
*******MENU*******
1) Continue
2) Quit
Enter your choice: 2
Thank You.