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From Huntsman84 <tpgarci...@gmail.com>
Subject Re: Searching for partial matches
Date Mon, 04 May 2009 16:48:59 GMT

My aim is to handle * phrases *, as you say, but I don't know how to build a
WildCardQuery for that purpose... I read in the documentation that those
kind of queries can't start with '*' (e.g. * phrase *), so I tryed
MultiPhraseQuery instead.

Forgive me if I am too newbie, 10 days ago I didn't know this tool
existed...


Erick Erickson wrote:
> 
> Why are you using MultiPhraseQuery? It appears (warning,
> I haven't really used it) to be designed to handle *phrases*.
> You're problem statement isn't looking at phrases at all,
> just a wildcard single terms. And you're supposed to
> call the first MPQ.add with, say, the first word of the
> *phrase*, not a term vector. So what happens when your
> first add is an array of Terms I have no clue......
> 
> So I'd instead use RegexTermEnum (or possibly
> WildcardTermEnum, don't know how this latter
> works with leading wildcards, you'll have to check)
> to enumerate the first 200 matching terms, and
> add them clause by clause to a BooleanQuery,
> and then use the BooleanQuery to search......
> 
> But I'd also have to ask how users will feel about
> getting some small partial match of the "real" data
> set. By taking the first 200 Terms you find, it looks
> to the user either arbitrary on incomplete. Think about
> using, say, WildcardTermEnum to construct a Filter
> that you then pass to your search. Constructing
> Filters is quite fast, although you lose the wildcarded
> terms' contributions to the score (don't worry about this
> last IMO).
> 
> 
> Best
> Erick
> 
> On Mon, May 4, 2009 at 11:21 AM, Huntsman84 <tpgarcia84@gmail.com> wrote:
> 
>>
>> Hi
>>
>> I've tryed this with MultiPhraseQuery, but it always returns me all
>> documents of the index, no matter what expression I use.
>>
>> I've read that adding a set of terms wich their values are all the
>> entered
>> query (e.g. "str"), the search works as the symbol "*" (e.g. "str*"), so
>> I
>> tryed that.
>>
>> My code is like this:
>>
>> // prompt the user
>> System.out.println("Enter query: ");
>>
>> String line = in.readLine(); //if I put "str", I want all matches like
>> "string", "strong", "astray"....
>>
>> line = line.trim();
>>
>> //I thought this would be ok...
>> MultiPhraseQuery mpquery = new MultiPhraseQuery();
>> TermEnum te = reader.terms(new Term("contents",line));
>>
>> /*Home-made conversion from TermEnum to Term[]... I get just 200 matches,
>> I
>> don't want my
>>   machine busy...*/
>> Term[] terms = new Term[200];
>> int j=0;
>>
>> while(te.next() && j<200){
>>    terms[j] = te.term();
>>    j++;
>> }
>>
>> mpquery.add(terms);
>>
>> Query query = parser.parse(line);
>> System.out.println("Searching for: " + query.toString(field));
>>
>> Date start = new Date();
>>
>> Hits hits = searcher.search(mpquery);
>> for(int k = 0; k<100; k++){
>>    //when I print the results of the search, none of the values match
>> with
>> the query...
>>    System.out.println(hits.doc(k).getField("contents").stringValue());
>> }
>>
>>
>>
>> Ian Lea wrote:
>> >
>> > Hi
>> >
>> >
>> > This is possible.  There is an entry on wildcards in the FAQ.  See
>> > also RegexQuery and search the mailing lists for ngrams.
>> >
>> > Depending on your setup and requirements you may need to be aware of
>> > the performance implications of wild card searching, particularly
>> > leading wildcards as will be required for the example you give.  See
>> > the FAQ and javadocs for WildcardQuery.
>> >
>> >
>> > --
>> > Ian.
>> >
>> > On Thu, Apr 30, 2009 at 11:46 AM, Huntsman84 <tpgarcia84@gmail.com>
>> wrote:
>> >>
>> >> Hello,
>> >>
>> >>
>> >>
>> >> I am new to Lucene, and I don't know if it is possible to obtain
>> results
>> >> providing part of the keyword.
>> >>
>> >>
>> >>
>> >> For example, if I try to search "in", it should return all matches
>> with
>> >> "string", "meaning", "trinity"...
>> >>
>> >>
>> >>
>> >> Am I expecting too much?
>> >>
>> >>
>> >>
>> >> Thank you so much!
>> >
>> > ---------------------------------------------------------------------
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>> > For additional commands, e-mail: java-user-help@lucene.apache.org
>> >
>> >
>> >
>>
>> --
>> View this message in context:
>> http://www.nabble.com/Searching-for-partial-matches-tp23313810p23370618.html
>> Sent from the Lucene - Java Users mailing list archive at Nabble.com.
>>
>>
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>>
>>
> 
> 

-- 
View this message in context: http://www.nabble.com/Searching-for-partial-matches-tp23313810p23372180.html
Sent from the Lucene - Java Users mailing list archive at Nabble.com.


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