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Re: st: drop range of variables meeting condition in another variable


From   Nick Cox <njcoxstata@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: drop range of variables meeting condition in another variable
Date   Mon, 18 Mar 2013 20:02:23 +0000

At a guess, you want to -drop- all gene variables that are identically
zero. That is

findname gene*, all(@==0)

drop `r(varlist)'

where -findname- is to be found by -search findname- and downloaded
from the Stata Journal files.

It is not so difficult without -findname-, either.

foreach v of var gene* {
       su `v', meanonly
       if r(max) == 0 local todrop `todrop' `v'
}
drop `v'

Nick

On Mon, Mar 18, 2013 at 7:53 PM, Tamer Farag
<tfarag@medicine.umaryland.edu> wrote:

> I am working with a case control dataset with gene clusters variables.  I have approx 100 observations, a handful of essential variables, but approx. 14,000 variables for each observation that represent gene clusters (absent/present, 0/1).  The gene variables are all located next to each other in the dataset (i.e., gene1-gene14000).
>
> I would like to drop variables for gene clusters that are not present among my cases.  Obviously, specifying each gene cluster variable would be impractical.
>
> Is there any way to do this in Stata?  I'm stumped.

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