def search(self, text):
        qtrigrams = utils.get_trigrams(text)
        scores = []  
        for tid, dtrigrams in self.tweets.iteritems():
            union = len(qtrigrams | dtrigrams)
            intersection = len(qtrigrams & dtrigrams)
            scores.append((tid, intersection/float(union)))
        #print scores

        
        scores = sorted(scores, key=lambda tup: tup[1])[::-1]

        return scores
 def index_tweet(self, tweet):
     tid = tweet['id']
     text = tweet['text']
     trigrams = utils.get_trigrams(text)
     self.tweets[tid] = trigrams
     self.N += 1