Python: intersection of lists/sets

Answer 1

Would the built-in set type work for you?

$ python
Python 2.6.5 (r265:79063, Jun 12 2010, 17:07:01)
[GCC 4.3.4 20090804 (release) 1] on cygwin
Type "help", "copyright", "credits" or "license" for more information.
>>> hello = set([1,2,5,6])
>>> world = set([1,3,5,7,8])
>>> hello & world
set([1, 5])

Answer 2

I want to generalize it for multiple tokens

def boolean_search_and_multi(self, text):
    and_tokens = self.tokenize(text)
    results = set(self._inverted_index[and_tokens[0]])
    for tok in and_tokens[1:]:
        results.intersection_update(self._inverted_index[tok])
    return list(results)