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Re: st: Using the -if- qualifier with a string variable

From   Roger Newson <>
Subject   Re: st: Using the -if- qualifier with a string variable
Date   Sun, 03 Apr 2005 16:26:22 +0100

At 16:15 03/04/2005, Louis wrote:
Dear All,
Can the -if- qualifier be used with a string variable? If so, how is it done? I gave the following command, and had the shown result:
. keep if facility==bir
bir not found

"facility" is a string variable and "bir" is one of the values "facility" takes.
You should type

keep if facility=="bir"

That way, Stata knows that "bir" is a string value. If you type

keep if facility==bir

then Stata will look for a string variable named bir, and will complain if it doesn't find it.

I hope this helps.


Roger Newson
Lecturer in Medical Statistics
Department of Public Health Sciences
Division of Asthma, Allergy and Lung Biology
King's College London

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