Returning result of palindrome program using while-loop

Question

n = str(input('Enter the string:'))
def palindrome(n):
    index = 0
    check = True
    while index<int(len(n)/2):
        if n[index]==n[-1-index]:
            index+=1
            return True
            break
        return False
if palindrome(n)==True:
    print('palindrome')
else:
    print('not palindrome')

I am not getting the correct answer for this palindrome program.

Answer 1

使用raw_input：

n = str(raw_input('Enter the string:'))

Answer 2

def palindrome(my_string):
    reverse_string = my_string[::-1]
    if list(my_string)==list(reverse_string):
       return True
    else:
       return False
my_string = input("ENTER THE STRING ")
if(palindrome(my_string)):
    print("Palindrome")
else:
    print("Not Palindrome")

Answer 3

The classic solution:

def palindrome(n):
    start = 0
    end = len(n) - 1
    while (start < end):
        if (n[start] != n[end]):
            return False
        start = start + 1
        end = end - 1
    return True

Answer 4

while index < int(len(n) / 2):
    if n[index] != n[len(n) - index - 1]:
        return False
    index+=1
return True

Answer 5

Your check is broken. Look at return True :

def palindrome(n):
    index = 0
    check = True
    while index<int(len(n)/2):
        if n[index]==n[-1-index]:
            index+=1  # only increment on match !!!
            return True  # return True on *first* match !!!
            break  # unnecessary, return exits the loop
        return False  # never reached, but would only trigger if there are no matches

Basically, you go through your string and on the first match you report True. So if first and last letter are the same, True is returned. Only if no pair of characters matches, you return False . This is the opposite of what want to check. It should be this instead:

def palindrome(n):
    index = 0
    check = True
    while index < len(n)/2:
        if n[index] != n[-1-index]:
            return False  # one didn't match, cannot be a palindrome
        index+=1
    return True  # all did match, is a palindrome