I searched my question in the mail archive, and found that I really want to
get a phrase frequency, it is an old question which was not solved well.
I traced Lucene source code, and discover that I can get a phrase's IDF from
the Hits object
weight= PhraseQuery$PhraseWeight (id=62)
idf= 8.3973465
queryNorm= 0.11908524
queryWeight= 1.0
similarity= DefaultSimilarity (id=66)
this$0= PhraseQuery (id=29)
value= 8.3973465
and we can get an approximate formula: score = tf * idf
so: tf(phrase)= score / idf(phrase)
is this correct?
----- Original Message -----
From: "Daniel Noll" <[EMAIL PROTECTED]>
To: <java-user@lucene.apache.org>
Sent: Thursday, February 23, 2006 8:57 AM
Subject: Re: How can I get a term's frequency?
sog wrote:
en, but IndexReader.getTermFreqVector is an abstract method, I do not
know how to implement it in an efficient way. Anyone has good advise?
You probably don't need to implement it, it's been implemented already.
Just call the method.
I can do it in this way:
QueryTermVector vector= new QueryTermVector(Document.getValues(field));
freq = result.getTermFrequencies();
I'm not sure because I've never used QueryTermVector before, but the
fact that QueryTermVector doesn't take an IndexReader as a parameter is
a good indication that it can't tell you anything about the frequency of
the term in your documents.
Daniel
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Daniel Noll
Nuix Australia Pty Ltd
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