Check for Palindrome in Python

Check for Palindrome in Python

A palindrome is a string that reads the same forwards and backwards, such as “racecar” or “madam”. This problem builds directly on string reversal.

Simple Solution

def is_palindrome(s):
    return s == s[::-1]

# Examples
print(is_palindrome("racecar"))  # True
print(is_palindrome("hello"))    # False

Case-Insensitive Check

def is_palindrome_ci(s):
    s = s.lower().replace(" ", "")
    return s == s[::-1]

print(is_palindrome_ci("A man a plan a canal Panama"))  # True

Alphanumeric Only

import re

def is_palindrome_clean(s):
    s = re.sub(r'[^a-zA-Z0-9]', '', s).lower()
    return s == s[::-1]

print(is_palindrome_clean("Was it a car or a cat I saw?"))  # True

Key Takeaway

The core check is always s == s[::-1]. Real-world usage requires normalizing the string (lowercase, remove spaces/punctuation) before comparing.