Check if the given string is Palindrome or not in Python

Understanding Palindrome

A palindrome is a string that reads the same forward and backward.

We will explore three different methods to check if a string is a palindrome using Python.

Method 1: Using a Loop

This method iterates through the string and checks if it is a palindrome.

def is_palindrome(s):
    l, r = 0, len(s) - 1
    while l < r:
        if s[l] != s[r]:
            return False
        l += 1
        r -= 1
    return True

# Example usage
s = "madam"
print("Palindrome" if is_palindrome(s) else "Not a Palindrome")

Input: madam
Output: Palindrome

Method 2: Using Recursion

This method checks palindrome property recursively.

def is_palindrome_recursive(s, l, r):
    if l >= r:
        return True
    if s[l] != s[r]:
        return False
    return is_palindrome_recursive(s, l + 1, r - 1)

# Example usage
s = "racecar"
print("Palindrome" if is_palindrome_recursive(s, 0, len(s) - 1) else "Not a Palindrome")

Input: racecar
Output: Palindrome

Method 3: Using String Reverse

This method reverses the string and compares it with the original.

s = "hello"
rev = s[::-1]
print("Palindrome" if s == rev else "Not a Palindrome")

Input: hello
Output: Not a Palindrome