topic Re: data manipulation in SAS Data Management

data manipulation

CynthiaFan — Wed, 07 Oct 2015 21:52:17 GMT

Hi everybody,

I have a question about data management.

According to the labdate, extract the earliest 2 labs named as “b” after testdate for each ID.

Thank you so much,

Here is the dataset

id	lab	testdate	labdate
1	a	1/1/2015	1/2/2015
1	a	1/1/2015	1/3/2015
1	b	1/1/2015	12/1/2014
1	b	1/1/2015	1/2/2015
1	b	1/1/2015	1/3/2015
1	b	1/1/2015	1/4/2015
2	a	2/1/2015	1/2/2015
2	a	2/1/2015	2/1/2015
2	b	2/1/2015	2/1/2015
2	b	2/1/2015	2/2/2015
2	b	2/1/2015	2/3/2015
2	b	2/1/2015	2/4/2015
3	a	3/1/2015	2/1/2015
3	a	3/1/2015	3/1/2015
3	b	3/1/2015	4/1/2015
3	b	3/1/2015	3/2/2015
4	b	4/1/2015	1/1/2015
4	a	4/1/2015	4/1/2015
4	a	4/1/2015	5/1/2015
4	b	4/1/2015	5/2/2015
4	b	4/1/2015	5/3/2015

Re: data manipulation

Patrick — Wed, 07 Oct 2015 22:01:14 GMT

This looks like a study question to me. If so then you should first spend some of your own time with it and only post a question if you get stuck.

If you get stuck: Please post the code you've got already and explain what's not working.

It would also help if you could post data as a SAS data step creating a SAS table.

Re: data manipulation

PGStats — Wed, 07 Oct 2015 22:15:30 GMT

Is this a homework? In any case, experiment with the following to understand why it works.


proc sort data=have; by id lab labdate; run;

data want;
set have; by id;
where lab="b" and labdate>testdate;
if first.id then order = 0;
order + 1;
if order < 3 then output;
drop order;
run;

proc print data=want noobs; run;

Re: data manipulation

CynthiaFan — Wed, 07 Oct 2015 23:51:31 GMT

thank you. I will learn to ask question more professionally.

Re: data manipulation

CynthiaFan — Wed, 07 Oct 2015 23:55:50 GMT

Thank you for the response especially for the part of obtaining the first and second earliest dates.