st: Re: How to list just the first case meeting a selection criterion?

["Michael Blasnik" <michael.blasnik@verizon.net>]

Given the large dataset, I would just drop all of the cases after the first 
for each criteria grouping, the you can list whatever you like quickly and 
easily:

bysort county precinct: keep if _n==1

Then you could:

list if county==xxx & precinct==y

It will be much faster working with the reduced dataset.  Just remember not 
to save,replace.

Michael Blasnik
michael.blasnik@verizon.net

----- Original Message ----- 
From: "paul gronke" <pgronke@gmail.com>
To: <statalist@hsphsun2.harvard.edu>
Sent: Monday, June 27, 2005 7:09 PM
Subject: st: How to list just the first case meeting a selection criterion?



> I am dealing with an extremely large (2 gig) dataset and wish to list
> just the first case that meets a set of criteria.  There are about 200
> separate sets of criteria (county and precinct values).
>
> Thus, I'd like a command that does something like:
>
> list name address1 address2 county precinct city state
>     if [first one of] county=VALUE & precinct=VALUE
>
> repeated about 200 times.
>
> I could do this with
>     sample 1 if CRITERIA
>
> but that seems needless complex, especially since all I want is the
> first case that meets 200 combinations of county and precinct.
>
> Thanks
> Paul Gronke
> Reed College
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