Palindrom

A palindrome is a word, number, phrase, or other sequence of symbols that reads the same backwards as forwards, such as the words madam or racecar, the date and time 11/11/11 11:11, and the sentence: "A man, a plan, a canal – Panama".

run = True
while run:
    user_input = input('Please type a word or number to check if it is a Palindrom or not or type exit: ')
    if user_input == 'exit':
        run = False
        break
    user = ''.join(filter(str.isalnum, user_input)) # removes all the non-alphanumic characters.
    lowercase = user.lower() # turn the input word into a lowercase word - dows nothing on numbers.
    characters = list(lowercase) # turn the input word into a list of characters.
    length = len(characters) # counts the number of characters
    for c,i in zip(characters, range(length)):
        reverse_char = characters[(length - 1 - i)]
        if c != reverse_char:
            print(False)
            break
        else :
            if i == length-1:
                print(True)