Hello,
This example code is takne from this paper (https://www.pharmasug.org/proceedings/2013/TF/PharmaSUG-2013-TF12.pdf). I don' think we need to retain ldosdt variable.
DATA ds1a (keep=usubjid fdosdt ldosdt);
set ipadmin;
by usubjid startdt;
retain fdosdt ldosdt;
if first.usubjid then
fdosdt = startdt;
if last.usubjid then
do;
ldosdt = startdt;
output;
end;
run;
I tried to simulate the above with this program.
data test;
input id $ x;
cards;
a 1
a 2
a 3
;
run;
data want;
set test;
by id;
retain f_;
if first.id then
f_=x;
if last.id then
do;
l_=x;
output;
end;
run;
You are correct .. you don't have to retain the 2nd variable. Doesn't hurt, but definitely not necessary.
Art, CEO, AnalystFinder.com
You are correct .. you don't have to retain the 2nd variable. Doesn't hurt, but definitely not necessary.
Art, CEO, AnalystFinder.com
@art297 Thanks, Art.
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