Yes, there's a difference because each replacement is done separately.
The first example will replace every non-word character (\W) with your replacement string.
The first example will replace every non-word character (\W) with your replacement string.
>>> re.sub(r"\W", "X", "Hello, there!") 'HelloXXthereX'The second will replace every group of consecutive non-word characters with a single instance of the replacement string.
>>> re.sub(r"\W+", "X", "Hello, there!") 'HelloXthereX'