Retain Information For a Given ID

[mariko5797]

See Attached. Essentially, I want to have the BMI and treatment group repeated for the given ID. Then I want to assess whether the time frame was during or after by comparing DATE_1 to DATE_2. If DATE_2 occurred before the last DATE_1 for "during", then I want the time period for the X measurements to be labeled "during". If DATE_2 occurred after the first DATE_1 for "after", then I want the time period for X measurements to be labeled "after". I have attempted using the retain statement, but it doesn't seem to do what I expected it to. It seemed to have no effect on the data.

proc sort data = working nodupkey;
 by ID PERIOD DATE_1;
 run; 

data working; 
set working; 
by ID; 
retain TRT BMI DATE_1; 
run; 

[mariko5797]

I'm not sure why, but I didn't have the text tools to make the post easy to follow initially. Here's the code attempt rewritten:

proc sort data = working nodupkey; 
 by ID PERIOD DATE_1; 
run; 

data working; 
 set working; 
 by ID; 
 retain TRT BMI DATE_1; 
run;
 /* also tried to retain X1, X2, X3 instead */

[Reeza]

Not sure why your post didn't work but I edited it.

Retain doesn't really work on existing variables so if you want to use retain type functionality, create a new variable to hold the values. Looking at the Excel, RETAIN is not the correct solution here. UPDATE may be more appropriate.