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Re: Tsearch2 question: getting histogram of the vector elements

From: Oleg Bartunov <oleg(at)sai(dot)msu(dot)su>
To: Rajesh Kumar Mallah <mallah(at)trade-india(dot)com>
Cc: pgsql-sql(at)postgresql(dot)org
Subject: Re: Tsearch2 question: getting histogram of the vector elements
Date: 2004-03-11 09:01:37
Message-ID: Pine.GSO.4.58.0403111159240.25727@ra.sai.msu.su (view raw or flat)
Thread:
Lists: pgsql-sql
Read
http://www.sai.msu.su/~megera/oddmuse/index.cgi/Tsearch_V2_Notes
("Check words statistics")

tsearch2 comes with stat function.

for example - top 10 words from apod (Astronomy picture of the day):

select * from stat('select ti from apod') order by ndoc desc, nentry desc,word limit 10;

  word  | ndoc | nentry
--------+------+--------
 year   | 1283 |   2064
 star   | 1273 |   3908
 imag   | 1267 |   1967
 light  | 1232 |   2206
 pictur | 1177 |   1442
 earth  | 1059 |   1798
 visibl |  992 |   1259
 bright |  936 |   1335
 котор  |  903 |   1441
 эт     |  879 |   1397



	Oleg

On Thu, 11 Mar 2004, Rajesh Kumar Mallah wrote:

>
> Greetings!
>
> My original problem is to de duplicate a list of  around 0.3 million
> company names.
>
> Since a company name can be potentially (mis)spelt in numerous ways
> exactmatch
> obviously wont work.
>
> To make the searches faster i am using tsearch. For each company name i
> want to
> search other companies whose name is similar to the company in question.
>
> Since inclusion of all the vector elements of a given company reduces the
> chance of matching i am thinking of excluding the high frequency words
> from the query.
>
> Hence i need to find the high frequency elements like say 'consulting' ,
> 'limited' , 'Private'
> 'Industries' that occur commonly in company names.
>
> In my table i have populated the co_name_vec feild as
> strip(to_tsvector(co_name))
> can anyone help me analyzing the co_name_vec for the high frequency words?
>
> Also i would like to know alternate / better solution to this problem.
>
>
> Regds
> Mallah.
>
>
>
> SAMPLE DATA.
>
> +-----------------------------------------------------+----------------------------------------------------------+
> |                       co_name
> |                       co_name_vec                        |
> +-----------------------------------------------------+----------------------------------------------------------+
> | European Trade Partner & Consulting                 | 'trade'
> 'consult' 'partner' 'european'                   |
> | Gulbrandsen Chemicals Pvt. Ltd.                     | 'ltd' 'pvt'
> 'chemic' 'gulbrandsen'                       |
> | Govt. of Karnataka, Vision Group on Biotechnology   | 'govt' 'group'
> 'vision' 'karnataka' 'biotechnolog'       |
> | Digital Globalsoft Ltd. (A Hewlett Packard Company) | 'ltd' 'digit'
> 'compani' 'hewlett' 'packard' 'globalsoft' |
> | Shanon Construction Material Industries             | 'materi'
> 'shanon' 'industri' 'construct'                 |
> | singpore india trade rsources company               | 'india' 'trade'
> 'rsourc' 'compani' 'singpor'             |
> | RGV TELECOM CONSULTANTS PVT. LTD.                   | 'ltd' 'pvt'
> 'rgv' 'consult' 'telecom'                    |
> | avid information search and documents (p) ltd.      | 'p' 'ltd' 'avid'
> 'inform' 'search' 'document'            |
> | Tavant Technologies India (P) Ltd.                  | 'p' 'ltd'
> 'india' 'tavant' 'technolog'                   |
> | Maschinen Fabrik (India) Pvt. Ltd                   | 'ltd' 'pvt'
> 'india' 'fabrik' 'maschinen'                 |
> | Manishri Refractories and Ceramics Pvt. Ltd.        | 'ltd' 'pvt'
> 'ceram' 'manishri' 'refractori'              |
> | xavier export  import  management  institute        | 'manag' 'export'
> 'import' 'xavier' 'institut'            |
> | Best InformationTechnology ltd.                     | 'ltd' 'best'
> 'informationtechnolog'                      |
> | FutureCalls Technology Private Limited              | 'limit' 'privat'
> 'futurecal' 'technolog'                 |
> | mak controls and systems pvt ltd                    | 'ltd' 'mak'
> 'pvt' 'system' 'control'                     |
> | NATIONAL RESEARCH CENTRE FOR CASHEW                 | 'centr' 'cashew'
> 'nation' 'research'                     |
> | The Madras Aluminium Company Ltd.                   | 'ltd' 'madra'
> 'compani' 'aluminium'                      |
> | Shriram Institute for Industrial Research           | 'shriram'
> 'industri' 'institut' 'research'               |
> | All India Carpet Trade Fair Committee               | 'fair' 'india'
> 'trade' 'carpet' 'committe'               |
> | Tuff Security & Allied Services                     | 'alli' 'tuff'
> 'secur' 'servic'                           |
> +-----------------------------------------------------+----------------------------------------------------------+
> (20 rows)
>
>
> ---------------------------(end of broadcast)---------------------------
> TIP 6: Have you searched our list archives?
>
>                http://archives.postgresql.org
>

	Regards,
		Oleg
_____________________________________________________________
Oleg Bartunov, sci.researcher, hostmaster of AstroNet,
Sternberg Astronomical Institute, Moscow University (Russia)
Internet: oleg(at)sai(dot)msu(dot)su, http://www.sai.msu.su/~megera/
phone: +007(095)939-16-83, +007(095)939-23-83

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