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# RE: st: how drop a block of cases based other variable values

 From Nick Cox To "'statalist@hsphsun2.harvard.edu'" Subject RE: st: how drop a block of cases based other variable values Date Fri, 9 Dec 2011 15:06:39 +0000

```If Daniel's values for -winner- are only 1 and missing, then

bysort r (winner) : drop if winner[1] == 1

will be sufficient.

Daniel's own code failed because the -bysort r:- makes no difference to whether -winner==1-.

But -winner[1]- under -by:- is the first value of -winner- in each group.

Nick
n.j.cox@durham.ac.uk

-----Original Message-----
From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Maarten Buis
Sent: 09 December 2011 13:53
To: statalist@hsphsun2.harvard.edu
Subject: Re: st: how drop a block of cases based other variable values

On Fri, Dec 9, 2011 at 2:45 PM, Daniel Marcelino wrote:
> can anyone point me how can I drop all observations belonging to
> "r" based on "winner" value? I meant, I don't wish to drop only
> observations where winner values is 1, but
> given I got a winner in "r==a" I want drop all observations of this group.

*------------ begin example --------------
clear
input str2 r byte(w v1 v2 winner)
"a" .5 1 2  .
"a" .1 2 3  .
"a" .9 3 2  1
"a" .9 3 4  1
"a" .2 4 5  .
"a" .3 5 1  .
"b" .4 1 2  .
"b" .1 2 3  .
"b" .7 3 4  .
"b" .8 4 1  .
"b" .8 4 5  .
"b" .9 5 1  .
end

bys r : egen byte todrop = total(winner)
drop if todrop
drop todrop
*------------- end example --------------------

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```