Regex: Matching a space-joined list of words, excluding last whitespace

How would I match a space separated list of words followed by whitespace and some optional numbers? I have this:

>>> import re
>>> m = re.match('(?P<words>(\S+\s+)+)(?P<num>\d+)?\r\n', 'Foo Bar  12345\r\n')
>>> m.groupdict()
{'num': '12345', 'words': 'Foo Bar  '}

I'd like the words group to not include the last whitespace(s) but I can't figure this one out. I could do a .strip() on the result but that's not as much fun :)

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Some strings to test and wanted result:

'Foo & Bar 555\r\n' =开发者_JAVA百科> {'num': '555', 'words': 'Foo & Bar'}

'Hello World\r\n' => {'num': None, 'words': 'Hello World'}

'Spam     99\r\n' => {'num': 99, 'words': 'Spam'}

'Number 1 666\r\n' => {'num': 666, 'words': 'Number 1'}

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I'm a bit confused by your double capturing group, and the fact that you're using \w but want to match a non-word character like & (maybe you mean \S, non-spaces, where you say \w...?), but, maybe...:

>>> import re
>>> r = re.compile(r'(?P<words>\w+(?:\s+\S+)*?)\s*(?P<num>\d+)?\r\n')
>>> for s in ('Foo & Bar 555\r\n', 'Hello World\r\n', 'Spam     99\r\n',
...           'Number 1 666\r\n'):
...   print s, r.match(s).groupdict()
... 
Foo & Bar 555
{'num': '555', 'words': 'Foo & Bar'}
Hello World
{'num': None, 'words': 'Hello World'}
Spam     99
{'num': '99', 'words': 'Spam'}
Number 1 666
{'num': '666', 'words': 'Number 1'}
>>>