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From "sog" <sogwhites...@gmail.com>
Subject phrase frequency??
Date Fri, 24 Feb 2006 01:27:00 GMT

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" <daniel@nuix.com.au>
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
>
>
>
>
> -- 
> Daniel Noll
>
> Nuix Australia Pty Ltd
> Suite 79, 89 Jones St, Ultimo NSW 2007, Australia
> Phone: (02) 9280 0699
> Fax:   (02) 9212 6902
>
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