Varianten - count vowels

#classic mit for .. in .. loop

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

#mit regex  
def count_vowels(s):
    return len(re.findall(r"[aeiouAEIOU]", s))

#mit list comprehesion
def count_vowels(s):
    return sum(1 for char in s if char.lower() in "aeiou")