NOT, exclude, prohibit, !, -

[Jon Crowell <jc...@dsg.harvard.edu>]

Hi.  I've been reading the Query Syntax page at
http://jakarta.apache.org/lucene/docs/queryparsersyntax.html and I'm not
sure I understand the difference between the prohibit operator (-) and the
exclude operator (!).

It seems that NOT is the exclude operator and the short form is !.  I quote:


     The NOT operator excludes documents that contain the
     term after NOT. This is equivalent to a difference
     using sets. The symbol ! can be used in place of the
     word NOT.

     To search for documents that contain "jakarta apache"
     but not "jakarta lucene" use the query: 

    "jakarta apache" NOT "jakarta lucene"


The minus sign (-) is described in its own section as the prohibit operator.
I quote:


     The "-" or prohibit operator excludes documents that
     contain the term after the "-" symbol.

     To search for documents that contain "jakarta apache"
     but not "jakarta lucene" use the query: 
     
     "jakarta apache" -"jakarta lucene"


My question is: what is the difference between these two operators?  If
there is no difference, then why are there two operators?

Thanks,

Jon


   




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Re: NOT, exclude, prohibit, !, -

[Otis Gospodnetic <ot...@yahoo.com>]

Hello,

I believe those are all the same.  I am writing this from an Internet
cafe in Sofia, Bulgaria, so I don't have access to QueryParser.jj, but
that's where you should look to see how NOT, ! and - are defined.
I believe they all exclude from the result, all documents that contain
the term or phrase that follows.

Otis


--- Jon Crowell <jc...@dsg.harvard.edu> wrote:
> Hi.  I've been reading the Query Syntax page at
> http://jakarta.apache.org/lucene/docs/queryparsersyntax.html and I'm
> not
> sure I understand the difference between the prohibit operator (-)
> and the
> exclude operator (!).
> 
> It seems that NOT is the exclude operator and the short form is !.  I
> quote:
> 
> 
>      The NOT operator excludes documents that contain the
>      term after NOT. This is equivalent to a difference
>      using sets. The symbol ! can be used in place of the
>      word NOT.
> 
>      To search for documents that contain "jakarta apache"
>      but not "jakarta lucene" use the query: 
> 
>     "jakarta apache" NOT "jakarta lucene"
> 
> 
> The minus sign (-) is described in its own section as the prohibit
> operator.
> I quote:
> 
> 
>      The "-" or prohibit operator excludes documents that
>      contain the term after the "-" symbol.
> 
>      To search for documents that contain "jakarta apache"
>      but not "jakarta lucene" use the query: 
>      
>      "jakarta apache" -"jakarta lucene"
> 
> 
> My question is: what is the difference between these two operators? 
> If
> there is no difference, then why are there two operators?
> 
> Thanks,
> 
> Jon
> 
> 
>    
> 
> 
> 
> 
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> To unsubscribe, e-mail: lucene-user-unsubscribe@jakarta.apache.org
> For additional commands, e-mail: lucene-user-help@jakarta.apache.org
> 


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