Hello,

So I have a longitudinal dataset with multiple observations.
One variables is whether subject had surgery at a certain time point:
character categorical variable (Yes, No).
So the observation is Y if the person had surgery and the rest are N.

Since I do not want to look at independent variables after surgery. I
want to delete all rows after the variable hits a Y. observations are
coded as N after surgery, as such if a Y is recorded I would like to
delete that along with the N at the rest of the time points for a
certain subject. Please look at how it looks below:

subject  sx
1           N
1           N
1           Y   how to Delete rows from here on for subject 1
1           N
1           N
2           N
2           Y  how to Delete rows from here on for subject 2
2           N
3           N
3           N
3           Y how to Delete rows from here on for subject 3
3           N
3           N

"jiji" <joelleahallak@gmail.com> wrote in message
news:c97d19f4-cbec-444f-927b-c7a444479944@x22g2000yqx.googlegroups.com...
> Hello,
>
> So I have a longitudinal dataset with multiple observations.
> One variables is whether subject had surgery at a certain time point:
> character categorical variable (Yes, No).
> So the observation is Y if the person had surgery and the rest are N.
>
> Since I do not want to look at independent variables after surgery. I
> want to delete all rows after the variable hits a Y. observations are
> coded as N after surgery, as such if a Y is recorded I would like to
> delete that along with the N at the rest of the time points for a
> certain subject. Please look at how it looks below:
>
> subject  sx
> 1           N
> 1           N
> 1           Y   how to Delete rows from here on for subject 1
> 1           N
> 1           N
> 2           N
> 2           Y  how to Delete rows from here on for subject 2
> 2           N
> 3           N
> 3           N
> 3           Y how to Delete rows from here on for subject 3
> 3           N
> 3           N

Presumably, your data are sorted by subject and timepont.  In that case,
something like this (untested) code should do:

data fee;
   set fie;
   by subject;
   if first.subject then dleet = 0;
   if sx = 'Y' then dleet = 1;
   if dleet then delete;
run;

There is probably an easier way, but I think that the following will
do what you want:

data have;
  input subject  sx $;
  cards;
1           N
1           N
1           Y
1           N
1           N
2           N
2           Y
2           N
3           N
3           N
3           Y
3           N
3           N
;

data want;
  set have;
  retain keep_going;
  by subject;
  if first.subject then keep_going=1;
  if keep_going eq 1 then output;
  if trim(left(sx)) eq "Y" then keep_going=0;
run;

HTH,
Art
-------------
On Mar 1, 4:58 pm, jiji <joelleahal...@gmail.com> wrote:
> Hello,
>
> So I have a longitudinal dataset with multiple observations.
> One variables is whether subject had surgery at a certain time point:
> character categorical variable (Yes, No).
> So the observation is Y if the person had surgery and the rest are N.
>
> Since I do not want to look at independent variables after surgery. I
> want to delete all rows after the variable hits a Y. observations are
> coded as N after surgery, as such if a Y is recorded I would like to
> delete that along with the N at the rest of the time points for a
> certain subject. Please look at how it looks below:
>
> subject  sx
> 1           N
> 1           N
> 1           Y   how to Delete rows from here on for subject 1
> 1           N
> 1           N
> 2           N
> 2           Y  how to Delete rows from here on for subject 2
> 2           N
> 3           N
> 3           N
> 3           Y how to Delete rows from here on for subject 3
> 3           N
> 3           N

> -----Original Message-----
> From: SAS(r) Discussion [mailto:SAS-L@LISTSERV.UGA.EDU] On Behalf Of Lou
> Sent: Monday, March 01, 2010 5:00 PM
> To: SAS-L@LISTSERV.UGA.EDU
> Subject: Re: How to delete rows in a sas dataset
>
> "jiji" <joelleahallak@gmail.com> wrote in message
> news:c97d19f4-cbec-444f-927b-
> c7a444479944@x22g2000yqx.googlegroups.com...
> > Hello,
> >
> > So I have a longitudinal dataset with multiple observations.
> > One variables is whether subject had surgery at a certain time point:
> > character categorical variable (Yes, No).
> > So the observation is Y if the person had surgery and the rest are N.
> >
> > Since I do not want to look at independent variables after surgery. I
> > want to delete all rows after the variable hits a Y. observations are
> > coded as N after surgery, as such if a Y is recorded I would like to
> > delete that along with the N at the rest of the time points for a
> > certain subject. Please look at how it looks below:
> >
> > subject  sx
> > 1           N
> > 1           N
> > 1           Y   how to Delete rows from here on for subject 1
> > 1           N
> > 1           N
> > 2           N
> > 2           Y  how to Delete rows from here on for subject 2
> > 2           N
> > 3           N
> > 3           N
> > 3           Y how to Delete rows from here on for subject 3
> > 3           N
> > 3           N
>
> Presumably, your data are sorted by subject and timepont.  In that case,
> something like this (untested) code should do:
>
> data fee;
>    set fie;
>    by subject;
>    if first.subject then dleet = 0;
>    if sx = 'Y' then dleet = 1;
>    if dleet then delete;
> run;

You will need to add a retain statement to the data step (add it anywhere);

retain dleet;

Hope this is helpful,

Dan

Daniel J. Nordlund
Washington State Department of Social and Health Services
Planning, Performance, and Accountability
Research and Data Analysis Division
Olympia, WA  98504-5204

hi ... yet another idea (with the no+1 versus no=1, you can leave out the RETAIN statement) ...

data x;
input subject sx : $1.;
datalines;
1  N
1  N
1  Y
1  N
1  N
2  N
2  Y
2  N
3  N
3  N
3  Y
3  N
3  N
;
run;

data y;
set x;
by subject;
if first.subject then no=0;
if sx eq 'Y' then no+1;
if ^no;
drop no;
run;


--
Mike Zdeb
U@Albany School of Public Health
One University Place
Rensselaer, New York 12144-3456
P/518-402-6479 F/630-604-1475

> Hello,
>
> So I have a longitudinal dataset with multiple observations.
> One variables is whether subject had surgery at a certain time point:
> character categorical variable (Yes, No).
> So the observation is Y if the person had surgery and the rest are N.
>
> Since I do not want to look at independent variables after surgery. I
> want to delete all rows after the variable hits a Y. observations are
> coded as N after surgery, as such if a Y is recorded I would like to
> delete that along with the N at the rest of the time points for a
> certain subject. Please look at how it looks below:
>
> subject  sx
> 1           N
> 1           N
> 1           Y   how to Delete rows from here on for subject 1
> 1           N
> 1           N
> 2           N
> 2           Y  how to Delete rows from here on for subject 2
> 2           N
> 3           N
> 3           N
> 3           Y how to Delete rows from here on for subject 3
> 3           N
> 3           N
>