def with_regex(string):
    from re import findall
    return sorted(findall(r"[\w']+", string), key=lambda x: len(x), reverse=True)[0]

def with_replace(string):
    string = "".join([" " if let.lower() not in "qwertyuiopasdfghjklzxcvbnm" else let for let in string])
    return sorted(string.split(), key=lambda x: len(x), reverse=True)[0]