Xapian discuss - Jul 2015 - Get term from document by position

Hello. Is there any FAST way to get a term from  the xapian document by it's
position, something like
std::string term = Xapian::Document::GetTermByPosition(int position) ?

Below i have described a task that i am trying to solve, in case if somebody is
interested.




===========================================================================When
displaying search results, i would like to to display a piece of the document
that is related to the search string (snippet). I have the following idea:

1) first i have to find the positions of the search terms by using
Xapian::TermIterator::positionlist_begin() iterator.

2) second, i have to display terms that have positions that are close to the
search term position (several terms from the left, and several terms from the
right of the search term)

So, i know positions of the terms that i want to display. But how to get the
terms itself? Xapian::Document does not have something like
GetTermByPosition(int position).

Currently i am iterating through all of the terms, than through all of the
positions, something like this:

 for (term = xapian_database.termlist_begin(docid);
        term != xapian_database.termlist_end(docid); term++)
    {
           
    for (pos = xapian_database.positionlist_begin(docid, *term);
            pos != xapian_database.positionlist_end(docid, *term); pos++)
        {
        if ( (*pos) == position_of_my_term)) my_term= *term;

        }
    }

This does what i want, but this cycle takes too long to run. So, may there is a
better approach?

On 23 Jul 2015, at 13:30, john.alveris at Safe-mail.net wrote:
> Hello. Is there any FAST way to get a term from  the xapian document by
it's position, something like
> std::string term = Xapian::Document::GetTermByPosition(int position) ?
Not that I?m aware of. Snippet highlighting is something that was worked on for
a GSoC project a few years ago, and is mentioned in our FAQ:
<http://trac.xapian.org/wiki/FAQ/Snippets>. It?s not available in the 1.2
series, but as I understand it should work out of the box in 1.3.3.

Note that your suggested approach of going from terms to snippet doesn?t work in
the general case, because of issues like stemming. Instead, Mihai?s approach was
to use the matcher information to generate a snippet from the original,
unstemmed and untermed, text.

J

-- 
 James Aylett, occasional trouble-maker
 xapian.org