Logic Building/Phase 3 - Level 4: String-based Recursion/Program

Check Palindrome String Recursively

Check if string is palindrome recursively.

Logic BuildingAdvanced

Logic Building

def is_palindrome(s):
    # Base case
    if len(s) <= 1:
        return True
    
    # Check first and last
    if s[0].lower() != s[-1].lower():
        return False
    
    # Recurse on middle
    return is_palindrome(s[1:-1])

# Test
text = input("Enter a string: ")
if is_palindrome(text):
    print("Palindrome")
else:
    print("Not a palindrome")

Output

Enter a string: racecar
Palindrome

Enter a string: hello
Not a palindrome

Compare first and last, recurse on middle.

Key Concepts:

Base case: empty or single character
Check first == last
Recurse on s[1:-1] (middle part)

Reverse String Recursively

Count Vowels Recursively