topic Re: Variable Selection in SAS Programming

Variable Selection

Gregorytus07 — Fri, 01 Mar 2024 15:55:36 GMT

Hi everyone,

I have a dataset that contains multiple result rows for each study ID. I need help in writing a SAS code that selects the first result for each study ID. If the first result is 'See Text', then select the next result value for that study ID.

Thanks for your help.

Re: Variable Selection

PaigeMiller — Fri, 01 Mar 2024 16:12:09 GMT

Please clarify: your title says "Variable Selection" but your description implies you want to select rows. Which is it?

In either case, please provide sample data, and show us the desired output.

Re: Variable Selection

Reeza — Fri, 01 Mar 2024 16:33:03 GMT

data want;
set have;
by studyID;
where firstResult ne 'See Text';
if first.studyID;
run;

Use FIRST assuming it's sorted and a WHERE to remove the SEE TEXT records.

@Gregorytus07 wrote:

Hi everyone,

I have a dataset that contains multiple result rows for each study ID. I need help in writing a SAS code that selects the first result for each study ID. If the first result is 'See Text', then select the next result value for that study ID.

Thanks for your help.

Re: Variable Selection

Gregorytus07 — Fri, 01 Mar 2024 16:54:51 GMT

@PaigeMiller Thanks for your feedback.

This is a sample data

DATA YOUR_DATASET;
INPUT STUDYID GLUCOSE$;
DATALINES;
1 100
1 120
1 See Text
2 85
2 95
3 See Text
3 110
4 See Text
4 80
4 90
;
RUN;

The desired output should be similar to this;

Study_id	Glucose
1	100
2	85
3	110
4	80

Re: Variable Selection

Gregorytus07 — Fri, 01 Mar 2024 16:56:47 GMT

@Reeza Thanks for sharing this. I will try it out.

Re: Variable Selection

Astounding — Fri, 01 Mar 2024 18:18:44 GMT

Is it possible that a StudyID has all its observations saying "No Text"? If so, the proposed solution will exclude that StudyID entirely. To guarantee selecting an observation for each StudyID, a slight variation would do the trick:

data want;
set have (where=(firstResult ne 'See Text'))
    have (where=(firstResult eq 'See Text'));
by studyID;
if first.studyID;
run;