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Re: st: Keep string data


From   Ronan Conroy <rconroy@rcsi.ie>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: Keep string data
Date   Fri, 09 Aug 2002 14:42:13 +0100

on 9/8/02 12:00 PM, christopher@fergusson030481.freeserve.co.uk at
christopher@fergusson030481.freeserve.co.uk wrote:

> The 
> variable name is siteterm and is stored at string10 type. When I am
> analysisng the data I need to keep and drop certain cancer sites
> however I am having trouble doing this. I have no problem dropping
> variables that are stored as int and byte types for example
> keep if year==1996
> but when I try to do the following
> keep if siteterm==lung
> I have the error "lung not found; r(111)" returned.

You're going to kick yourself. And I know this for a fact, because I once
spent 2 days going crazy over exactly the same problem in another stats
package!

Stata things that the expression `siteterm==lung' is asking it to test if
the variable siteterm has the same value as the variable lung.

To make it clear to Stata that the argument is a string, enclose it in
double quotes.

. keep if siteterm=="lung"

Note that this will not find "Lung" or "lung ", so tabulate your data to
make sure that site is always spelled the way you think it is.


Ronan M Conroy (rconroy@rcsi.ie)
Lecturer in Biostatistics
Royal College of Surgeons
Dublin 2, Ireland
+353 1 402 2431 (fax 2329)

--------------------
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