Python program to check if the given string is vowel Palindrome

In this article, we will learn how to check if a string becomes a palindrome after removing all consonants, keeping only the vowels.

Problem statement − We are given a string containing both vowels and consonants. We need to remove all consonants and check if the resulting vowel-only string is a palindrome.

A palindrome reads the same forwards and backwards. Our approach involves two steps: first extract only vowels from the string, then check if this vowel string is a palindrome.

Algorithm

The solution follows these steps ?

• Extract all vowels from the input string
• Check if the vowel string is a palindrome by comparing it with its reverse
• Return appropriate result based on the comparison

Complete Implementation

def extract_vowels(s):
    """Extract only vowels from the string"""
    vowels = ""
    for char in s.lower():
        if char in "aeiou":
            vowels += char
    return vowels

def is_palindrome(s):
    """Check if string is palindrome"""
    return s == s[::-1]

def is_vowel_palindrome(s):
    """Check if string becomes palindrome after removing consonants"""
    vowel_string = extract_vowels(s)
    
    # If no vowels found
    if not vowel_string:
        return False, "No vowels found"
    
    # Check if vowel string is palindrome
    if is_palindrome(vowel_string):
        return True, f"Vowel string '{vowel_string}' is palindrome"
    else:
        return False, f"Vowel string '{vowel_string}' is not palindrome"

# Test examples
test_strings = ["aeoea", "hello", "racecar", "programming", "aeiuoiea"]

for s in test_strings:
    result, message = is_vowel_palindrome(s)
    print(f"'{s}': {message}")

'aeoea': Vowel string 'aeoea' is palindrome
'hello': Vowel string 'eo' is not palindrome
'racecar': Vowel string 'aeea' is not palindrome
'programming': Vowel string 'oai' is not palindrome
'aeiuoiea': Vowel string 'aeiuoiea' is palindrome

Step-by-Step Example

Let's trace through the process with the string "aeoea" ?

def trace_vowel_palindrome(s):
    print(f"Original string: '{s}'")
    
    # Extract vowels
    vowels = ""
    for char in s.lower():
        if char in "aeiou":
            vowels += char
            print(f"Found vowel: '{char}', current vowel string: '{vowels}'")
    
    print(f"Final vowel string: '{vowels}'")
    print(f"Reversed vowel string: '{vowels[::-1]}'")
    print(f"Is palindrome? {vowels == vowels[::-1]}")

# Test with example
trace_vowel_palindrome("aeoea")

Original string: 'aeoea'
Found vowel: 'a', current vowel string: 'a'
Found vowel: 'e', current vowel string: 'ae'
Found vowel: 'o', current vowel string: 'aeo'
Found vowel: 'e', current vowel string: 'aeoe'
Found vowel: 'a', current vowel string: 'aeoea'
Final vowel string: 'aeoea'
Reversed vowel string: 'aeoea'
Is palindrome? True

Edge Cases

# Test edge cases
edge_cases = ["", "bcdfg", "a", "AeIoU", "xyz"]

for case in edge_cases:
    result, message = is_vowel_palindrome(case)
    print(f"'{case}': {message}")

'': No vowels found
'bcdfg': No vowels found
'a': Vowel string 'a' is palindrome
'AeIoU': Vowel string 'aeiou' is not palindrome
'xyz': No vowels found

Conclusion

This approach efficiently checks vowel palindromes by first extracting vowels and then verifying palindrome property. The solution handles edge cases like strings with no vowels and works with both uppercase and lowercase letters.