sas code help

[rashmirao99]

Hi ,

         I need to create baseline values: The dataset I have as follows:

subjid         paramcd     visit           aval

001              dbp            1               72

001              dbp           2                 60

001              dbp           3                 78

001              dbp          4                   80

The desired dataset:

subjid         paramcd     visit           aval        base

001              dbp            1               72          72

001              dbp           2                 60         72

001              dbp           3                 78         72

001              dbp          4                   80        72

if aval=72 is the baseline.

Thanks.

[novinosrin]

data have;
input subjid  $       paramcd   $  visit           aval;
cards;
001              dbp            1               72
001              dbp           2                 60
001              dbp           3                 78
001              dbp          4                   80
;

data want;
 set have;
 by subjid;
 retain base;
 if first.subjid then base =aval;
run;

Hi @rashmirao99  The idea is 

1. You need to assign the first observation of a by group i.e each subjid to a new variable called base

2. Retain the value of base once assigned across iterations within each subjid by group, otherwise the value of base is reinitialized to missing for each iteration of the datastep. 

[rashmirao99]

No. That doesn't work.  It only populates for the first record.

What I want is suppose I have something like this:

001              dbp            1               72
001              dbp           2                 60
001              dbp           3                 78
001              dbp          4                   80

001              hr             1                   45

001              hr             2                   55

001              hr             3                   60

and The output data I'm expecting is this:

subjid         test            visit          aval        base

001              dbp            1               72          72
001              dbp           2                 60         72
001              dbp           3                 78         72
001              dbp          4                   80        72

001              hr             1                   45       45

001              hr             2                   55       45

001              hr             3                   60       45.

 Thanks.

[novinosrin · Accepted solution]

Hi @rashmirao99  Here is a test-->

data have;
input subjid  $       paramcd   $  visit           aval;
cards;
001              dbp            1               72
001              dbp           2                 60
001              dbp           3                 78
001              dbp          4                   80
001              hr             1                   45
001              hr             2                   55
001              hr             3                   60
;

data want;
 set have;
 by subjid paramcd;
 retain base;
 if first.paramcd then base =aval;
run;

subjid	paramcd	visit	aval	base
001	dbp	1	72	72
001	dbp	2	60	72
001	dbp	3	78	72
001	dbp	4	80	72
001	hr	1	45	45
001	hr	2	55	45
001	hr	3	60	45