topic Re: Outputting Obvservations until a criteria is met in SAS Programming

Outputting Obvservations until a criteria is met

Katie — Tue, 27 Dec 2016 20:20:42 GMT

Hello. Here is what I have:

PT_ID date result criteria_met

x 1/1/2015 500 yes

x 2/1/2015 470 no

x 3/1/2015 525 yes

z 2/2/2015 450 no

z 3/32015 575 yes

k 5/4/2015 650 yes

basically, what I want is all the data for a particular patient up through their first 'Yes' in the criteria_met column. So patient x will have 1 observation, patient z will have 2 and patient k will have 1 observation.

Any help is appreicated! Thank you!

Re: Outputting Obvservations until a criteria is met

Patrick — Tue, 27 Dec 2016 21:07:51 GMT

Code not tested but should do the job.

data want(drop=_output_flg);
  set have;
  by pt_id date;
  retain _output_flg;
  if first.pt_id then _output_flg=1;
  if _output_flg=1 then output;
  if upcase(criteria_met)='YES' then _output_flg=0;
run;

Re: Outputting Obvservations until a criteria is met

Jagadishkatam — Wed, 28 Dec 2016 01:59:02 GMT

Please try

data have;
input PT_ID$         date: ddmmyy10.           result    criteria_met$;
format date date9.;
cards;
x           1/1/2015         500           yes
x           2/1/2015         470           no
x            3/1/2015        525          yes
z            2/2/2015        450           no
z            3/3/2015         575         yes
k            5/4/2015        650         yes
;

proc sort data=have;
by  pt_id descending criteria_met  date;
run;

data want;
do until(first.pt_id);
set have;
  by pt_id descending criteria_met  date;
if first.pt_id then yesdate=date;
end;
do until(last.pt_id);
set have;
  by pt_id descending criteria_met  date;
if date<=yesdate then output;
format yesdate date9.;
end;
run;

Re: Outputting Obvservations until a criteria is met

mkeintz — Wed, 28 Dec 2016 02:47:35 GMT

You want to output all records up through the first positive (criteria_met='yes'). So all you need to do is keep a running count of the number of positives encountered (N_POS in the program below).

Notes:

The program below assumes the data are grouped by PT_ID (and sorted by date within each PT_ID group). But, while grouped by PT_ID, it appears not to be in ascending PT_ID order - hence the "by pt_id NOTSORTED". If it's not grouped, or not sorted by date within PT_ID, then sort dataset have by PT_ID/date first.
The subsetting "if n_pos=0" might make you think that only records BEFORE the first positive will be output. But note that N_POS is not updated until after the subsetting if - as a result the first positive will be output, even though N_POS has become 1. All subsequent records within a PT_ID will be filtered out. If you want to see the evidence remove the "drop n_pos" statement and look at the output.

data have;

input PT_ID$ date: ddmmyy10. result criteria_met$;

format date date9.;

cards;

x 1/1/2015 500 yes

x 2/1/2015 470 no

x 3/1/2015 525 yes

z 2/2/2015 450 no

z 3/3/2015 575 yes

k 5/4/2015 650 yes

;

data want;

set have;

by pt_id notsorted;

if first.pt_id then n_pos=0;

if n_pos=0;

n_pos + (criteria_met='yes');

drop n_pos;

run;