How to Reverse String Consonants without Affecting other Elements in Python

String consonants refer to the non-vowel sounds produced when pronouncing a string of characters. In this article, we will learn how to reverse only the consonants in a string without affecting the position of vowels and other characters using two different methods in Python.

Problem Example

Given a string, we want to reverse only the consonants while keeping vowels and special characters in their original positions ?

# Input and expected output
input_string = "tutorialspoint"
print("Before Reversing:", input_string)
# After reversing consonants: "tunopiaslroitt"

Before Reversing: tutorialspoint

Method 1: Using append() and join() Functions

This approach first collects all consonants, then replaces them in reverse order ?

def checkConsonant(char):
    # List of vowels
    vowels = ['a', 'e', 'i', 'o', 'u']
    # Check if character is not a vowel and is alphabetic
    return char.lower() not in vowels and char.isalpha()

def consonantReversing(inputString):
    # Convert string to list of characters
    char_list = list(inputString)
    
    # Collect all consonants
    consonants = []
    for char in char_list:
        if checkConsonant(char):
            consonants.append(char)
    
    # Replace consonants in reverse order
    consonant_index = len(consonants) - 1
    for i in range(len(char_list)):
        if checkConsonant(char_list[i]):
            char_list[i] = consonants[consonant_index]
            consonant_index -= 1
    
    return "".join(char_list)

# Test the function
print(consonantReversing("tutorialspoint"))
print(consonantReversing("python codes"))

tunopiaslroitt
sdc onhtoyep

Method 2: Using pop() Function and String Concatenation

This method uses pop() to remove consonants from the end of a list while building the result string ?

def consonantReversing(inputString):
    # Collect all consonants using list comprehension
    consonants = [c for c in inputString if c.lower() in 'bcdfghjklmnpqrstvwxyz']
    result = ""
    
    # Build result string
    for char in inputString:
        if char.lower() in 'bcdfghjklmnpqrstvwxyz':
            # Use pop() to get consonant from the end
            result += consonants.pop()
        else:
            # Keep vowels and special characters as is
            result += char
    
    return result

# Test the function
print(consonantReversing("tutorialspoint"))
print(consonantReversing("python codes"))
print(consonantReversing("Hello World!"))

tunopiaslroitt
sdcnoh toyep
dlroW olleH!

Comparison

How It Works

Both methods follow the same core principle:

1. Identify consonants: Extract all consonant characters from the string
2. Reverse order: Use the consonants in reverse order during replacement
3. Preserve positions: Keep vowels and special characters in their original positions

Conclusion

Both methods effectively reverse consonants while preserving vowel positions. The append() method offers clearer logic separation, while pop() provides a more concise single-pass solution. Choose based on your preference for readability versus brevity.