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Posted to user@lucenenet.apache.org by Michael Mitiaguin <mi...@gmail.com> on 2007/09/01 02:00:01 UTC
Re: using mutliple wildcards in a term?
Douglas,
I had a check with Lucene.Net 2..0.4 ( latest release , my understanding
2.1 hasn't been released yet , you just checked out from svn tree ? ) and
the following fragment does work for me.
searcher = new IndexSearcher(indexDir);
query = new WildcardQuery ( new Term ("description" ,
"*bbe*" )) ;
hits = searcher.Search ( query ) ;
For my index 85 hits , and lesser number 81 for "?ubbe*"
Did you mean you tried QueryParser with leading wildcard and it returned
hits ? I also would be interested to get a confirmation
this behaviour was changed in 2.1 comparing to 2.0.4 where exception is
thrown
[Lucene.Net.QueryParsers.ParseException] {"Lexical error at line 1,
column 1. Encountered: \"*\" (42), after : \"\""}
Lucene.Net.QueryParsers.ParseException
On 9/1/07, Douglas Smith (DataSmithy) <da...@googlemail.com> wrote:
>
> Hi Michael,
>
> FYI, with version 2.1, I am using wildcards with the standard query
> parser, and it seems to be working the way I expect. That is, if I put
> wildcards at the beginning *or* end or a word (prefix or suffix word
> part), I get different result counts compared to a word without any
> wildcards.
>
> However, I was not able to get wildcards to work with the WildcardQuery
> function searching on a single term (it returned no results). It is
> possible I may have not been using it correctly, since it was my first
> try.
>
> Also, my index is apparently small enough that I don't get a significant
> performance hit from using wildcards at the beginning of a term.
>
> /*Does anybody know if Lucene supports wildcards at the beginning *and*
> end of a term at the same time? I am getting no results when I do
> this. */
>
> Also from an interface design point of view, if Lucene does not support
> this, could it be argued that it should throw an error in this case,
> instead of returning no results?
>
> Michael Mitiaguin wrote:
> > Douglas,
> >
> > I never used it , but in "Lucene in Action" book we may read :
> > Wildcards at the beginning of a term are prohibited using QueryParser,
> but
> > an API-coded WildcardQuery may use leading wildcards (at the expense of
> > performance).
> >
> > Regards
> > Michael
> >
> > On 8/31/07, Douglas Smith <do...@aciwebs.com> wrote:
> >
> >> Hi everyone,
> >>
> >> Are wildcard queries intended to be able to support wildcards at the
> >> beginning *and* end of a term?
> >>
> >> I am getting search results when I use a single wildcard (*), but not
> >> when I use them at the begging *and* end of a word. The Lucene java
> >> documentation seems unclear on this point, but one of my requirements
> is
> >> to find word fragments in the middle of words.
> >>
> >>
> >> =====================================
> >> Douglas M. Smith
> >> =====================================
> >> Email: douglas.smith@aciwebs.com
> >> Yahoo: datasmithy@yahoo.com
> >> Jabber: datasmithy@jabber.parcellsharp.net
> >> =====================================
> >>
> >> "For years there has been a theory that millions of monkeys typing at
> >> random on millions of typewriters would reproduce the entire works of
> >> Shakespeare. The Internet has proven this theory to be untrue." -
> >> Unknown
> >>
> >>
> >>
> >>
> >
> >
>
> --
> ======================================
> Douglas M. Smith
> |--- DataSmithy ---|
>
> email: DataSmithy@gmail.com
> work: 540-322-2204
> home: 540-381-8939
> fax: 866-330-9401
> aim: datasmithy
> yahoo: datasmithy
> skype: datasmitty
> jabber: datasmithy@jabber.parcellsharp.net
> ======================================
>
>
>
RE: using mutliple wildcards in a term?
Posted by DIGY <di...@gmail.com>.
Hi,
There is a discussion about leading wildcards in Lucene which is available
in 2.1.
https://issues.apache.org/jira/browse/LUCENE-489
DIGY
-----Original Message-----
From: Michael Mitiaguin [mailto:mitiaguin@gmail.com]
Sent: Saturday, September 01, 2007 3:00 AM
To: lucene-net-user@incubator.apache.org
Subject: Re: using mutliple wildcards in a term?
Douglas,
I had a check with Lucene.Net 2..0.4 ( latest release , my understanding
2.1 hasn't been released yet , you just checked out from svn tree ? ) and
the following fragment does work for me.
searcher = new IndexSearcher(indexDir);
query = new WildcardQuery ( new Term ("description" ,
"*bbe*" )) ;
hits = searcher.Search ( query ) ;
For my index 85 hits , and lesser number 81 for "?ubbe*"
Did you mean you tried QueryParser with leading wildcard and it returned
hits ? I also would be interested to get a confirmation
this behaviour was changed in 2.1 comparing to 2.0.4 where exception is
thrown
[Lucene.Net.QueryParsers.ParseException] {"Lexical error at line 1,
column 1. Encountered: \"*\" (42), after : \"\""}
Lucene.Net.QueryParsers.ParseException
On 9/1/07, Douglas Smith (DataSmithy) <da...@googlemail.com> wrote:
>
> Hi Michael,
>
> FYI, with version 2.1, I am using wildcards with the standard query
> parser, and it seems to be working the way I expect. That is, if I put
> wildcards at the beginning *or* end or a word (prefix or suffix word
> part), I get different result counts compared to a word without any
> wildcards.
>
> However, I was not able to get wildcards to work with the WildcardQuery
> function searching on a single term (it returned no results). It is
> possible I may have not been using it correctly, since it was my first
> try.
>
> Also, my index is apparently small enough that I don't get a significant
> performance hit from using wildcards at the beginning of a term.
>
> /*Does anybody know if Lucene supports wildcards at the beginning *and*
> end of a term at the same time? I am getting no results when I do
> this. */
>
> Also from an interface design point of view, if Lucene does not support
> this, could it be argued that it should throw an error in this case,
> instead of returning no results?
>
> Michael Mitiaguin wrote:
> > Douglas,
> >
> > I never used it , but in "Lucene in Action" book we may read :
> > Wildcards at the beginning of a term are prohibited using QueryParser,
> but
> > an API-coded WildcardQuery may use leading wildcards (at the expense of
> > performance).
> >
> > Regards
> > Michael
> >
> > On 8/31/07, Douglas Smith <do...@aciwebs.com> wrote:
> >
> >> Hi everyone,
> >>
> >> Are wildcard queries intended to be able to support wildcards at the
> >> beginning *and* end of a term?
> >>
> >> I am getting search results when I use a single wildcard (*), but not
> >> when I use them at the begging *and* end of a word. The Lucene java
> >> documentation seems unclear on this point, but one of my requirements
> is
> >> to find word fragments in the middle of words.
> >>
> >>
> >> =====================================
> >> Douglas M. Smith
> >> =====================================
> >> Email: douglas.smith@aciwebs.com
> >> Yahoo: datasmithy@yahoo.com
> >> Jabber: datasmithy@jabber.parcellsharp.net
> >> =====================================
> >>
> >> "For years there has been a theory that millions of monkeys typing at
> >> random on millions of typewriters would reproduce the entire works of
> >> Shakespeare. The Internet has proven this theory to be untrue." -
> >> Unknown
> >>
> >>
> >>
> >>
> >
> >
>
> --
> ======================================
> Douglas M. Smith
> |--- DataSmithy ---|
>
> email: DataSmithy@gmail.com
> work: 540-322-2204
> home: 540-381-8939
> fax: 866-330-9401
> aim: datasmithy
> yahoo: datasmithy
> skype: datasmitty
> jabber: datasmithy@jabber.parcellsharp.net
> ======================================
>
>
>