Retain value based on another variable

[ari]

Have: 

ID	Day	R
1
1
1	Day 1
1	Day 2	run 0
1
1
1
1
1	Day1	run 1
1
1	Day2	run2
1
1

Want:

ID	Day	R
1
1
1	Day 1
1	Day 2	run 0
1		run 0
1		run 0
1		run 0
1		run 0
1	Day1	run 1
1		run 1
1	Day2	run2
1		run2
1		run2

I want to retain the value of R based on the value of Day (R value carried forward until the next Day

). Any help to achieve this using the retain function?

Thanks,

[data_null__]

This is pretty standard LOCF.

data run;
   infile cards missover;
   input ID Day &$ run &$;
   cards;
1 
1 
1 Day 1
1 Day 2  run 0
1 
1 
1 
1 
1 Day1  run 1
1 
1 Day2  run 2
1 
1 
;;;;
   run;
proc print;
   run;
data run;
   if 0 then set run;
   update run(keep=id obs=0) run(keep=id run);
   by id;
   set run(keep=day);
   output;
   run;
proc print;
   run; 

[ari]

Thanks @data_null__

[ari]

@data_null__. It works but difficult to understand to modify to copy the remaining variables as such in the dataset. My original dataset contains 50 variables and those be copied as such. Any pointers? Thanks

[data_null__]

---

@ari wrote:

@data_null__. It works but difficult to understand to modify to copy the remaining variables as such in the dataset. My original dataset contains 50 variables and those be copied as such. Any pointers? Thanks

---

Did you do any reading in the SAS online documentation about the statements used in the program?

change

set run(keep=day);

to

set run(drop=id run);

All variables in RUN except ID and RUN are added but their values are not carried forward.

The SET statement is to bring in all the variables that you do not want have values carried forward.