Python removing punctuation from unicode string except apostrophe

Question

I found several topics of this and I found this solution:

sentence=re.sub(ur"[^\P{P}'|-]+",'',sentence)

This should remove every punctuation except ', the problem is it also strips everything else from the sentence.

Example:

>>> sentence="warhol's art used many types of media, including hand drawing, painting, printmaking, photography, silk screening, sculpture, film, and music."
>>> sentence=re.sub(ur"[^\P{P}']+",'',sentence)
>>> print sentence
'

of course what I want is to keep the sentence without punctuation, and "warhol's" stays as is

Desired output:

"warhol's art used many types of media including hand drawing painting printmaking photography silk screening sculpture film and music"
"austro-hungarian empire"

Edit: I also tried using

tbl = dict.fromkeys(i for i in xrange(sys.maxunicode)
    if unicodedata.category(unichr(i)).startswith('P')) 
sentence = sentence.translate(tbl)

but this strips every punctuation

Answer 1

Specify all the elements you don't want removed, i.e. \w, \d, \s, etc. This is what the ^ operator means with in square brackets. (matches anything except)

>>> import re
>>> sentence="warhol's art used many types of media, including hand drawing, painting, printmaking, photography, silk screening, sculpture, film, and music."
>>> print re.sub(ur"[^\w\d'\s]+",'',sentence)
warhol's art used many types of media including hand drawing painting printmaking photography silk screening sculpture film and music
>>>