Hi All,
I am pretty new to Lucene and Pylucene. This is a problem when I am using
pylucene to write a customized analyzer, to tokenize text in to bigrams.
The code for analyzer class is:
class BiGramShingleAnalyzer(PythonAnalyzer):
def __init__(self, outputUnigrams=False):
PythonAnalyzer.__init__(self)
self.outputUnigrams = outputUnigrams
def tokenStream(self, field, reader):
result = ShingleFilter(LowerCaseTokenizer(Version.LUCENE_35,reader))
result.setOutputUnigrams(self.outputUnigrams)
#print 'result is', result
return result
I used ShingleFilter on the TokenStream produced by LowerCaseTokeinizer. When I
call the tokenStream function directly, it works just tine:
str = ‘divide this sentence'
bi = BiGramShingleAnalyzer(False)
sf = bi.tokenStream('f', StringReader(str))
while sf.incrementToken():
print sf
(divide this,startOffset=0,endOffset=11,positionIncrement=1,type=shingle)
(this sentence,startOffset=7,endOffset=20,positionIncrement=1,type=shingle)
The analyzer also works fine with QueryTermVector.
But when I tried to build a query parser using this analyzer, problem occurred:
parser = QueryParser(Version.LUCENE_35, 'f', bi)
query = parser.parse(str)
In query there is nothing.
After I add print statement in the tokenStream function, I found when I call
parser.parse(str), the print statement in tokenStream actually get called 3
times (3 words in my str variable). It seems to me the parser pre-processed the
str I passed to it, and call the tokenStream function on the result of the
pre-processing.
Any thoughts on how should I make the analyzer work, so that when I pass it to
query parser, the parser could parse a string into bigrams?
Thanks in advance!
Ke Wu
