Python program to check whether the string is Symmetrical or Palindrome

When checking if a string is symmetrical or palindromic, we need to understand two different concepts. A palindrome reads the same forwards and backwards (like "racecar"), while a symmetrical string has identical first and second halves (like "abcabc").

Understanding Palindromes vs Symmetrical Strings

A palindrome compares characters from both ends moving inward, while symmetry compares the first half with the second half of the string.

Complete Example

Here's a program that demonstrates both palindrome and symmetry checking ?

def check_palindrome(my_str):
    mid_val = (len(my_str)-1)//2
    start = 0
    end = len(my_str)-1
    flag = 0
    
    while(start < mid_val):
        if (my_str[start] == my_str[end]):
            start += 1
            end -= 1
        else:
            flag = 1
            break
    
    if flag == 0:
        print("The entered string is palindrome")
    else:
        print("The entered string is not palindrome")

def check_symmetry(my_str):
    n = len(my_str)
    flag = 0
    
    if n % 2:
        mid_val = n//2 + 1
    else:
        mid_val = n//2
    
    start_1 = 0
    start_2 = mid_val
    
    while(start_1 < mid_val and start_2 < n):
        if (my_str[start_1] == my_str[start_2]):
            start_1 = start_1 + 1
            start_2 = start_2 + 1
        else:
            flag = 1
            break
    
    if flag == 0:
        print("The entered string is symmetrical")
    else:
        print("The entered string is not symmetrical")

# Test with different strings
my_string = 'phphhphp'
print("Testing string:", my_string)
print("The method to check a palindrome is being called...")
check_palindrome(my_string)
print("The method to check symmetry is being called...")
check_symmetry(my_string)

print("\nTesting with 'racecar' (palindrome):")
check_palindrome('racecar')
check_symmetry('racecar')

print("\nTesting with 'abcabc' (symmetrical):")
check_palindrome('abcabc')
check_symmetry('abcabc')

Testing string: phphhphp
The method to check a palindrome is being called...
The entered string is palindrome
The method to check symmetry is being called...
The entered string is not symmetrical

Testing with 'racecar' (palindrome):
The entered string is palindrome
The entered string is not symmetrical

Testing with 'abcabc' (symmetrical):
The entered string is not palindrome
The entered string is symmetrical

How the Functions Work

Palindrome Check: Compares characters from start and end positions moving toward the center. If all pairs match, it's a palindrome.

Symmetry Check: Divides the string into two halves and compares corresponding positions. For odd-length strings, the middle character is ignored.

Key Differences

Conclusion

Palindromes read the same in both directions, while symmetrical strings have matching first and second halves. Both use similar loop logic but with different comparison strategies.