Count the number of vowels in Python

Understanding Vowel Counting

Vowel counting involves determining the number of vowels (a, e, i, o, u) in a given string.

We will explore three different methods to count the vowels in a string using Python.

Method 1: Using a Loop

This method iterates through the string and counts each vowel.

def count_vowels(string):
    count = 0
    vowels = "aeiouAEIOU"
    for char in string:
        if char in vowels:
            count += 1
    return count

string = input("Enter a string: ")
print("Number of vowels:", count_vowels(string))
            

Method 2: Using Recursion

This method counts vowels recursively.

def count_vowels_recursive(string, index=0):
    if index == len(string):
        return 0
    return (1 if string[index].lower() in "aeiou" else 0) + count_vowels_recursive(string, index + 1)

string = input("Enter a string: ")
print("Number of vowels:", count_vowels_recursive(string))
            

Method 3: Using List Comprehension

This method uses list comprehension to count vowels efficiently.

def count_vowels_list_comprehension(string):
    return sum(1 for char in string.lower() if char in "aeiou")

string = input("Enter a string: ")
print("Number of vowels:", count_vowels_list_comprehension(string))