LOCF

[Jack2012]

Dear All, 

I want to impute the missing obs with previous value, but have no idea, though I referred below good link: https://communities.sas.com/t5/SAS-Programming/Last-Observation-Carried-Foward/m-p/309339#M66511

Yes, all the missing variable should be imputed from the previous value, as this would be the accumulative number of subjects till some timepoint. 

The datafile in xlsx has been attached. 

Thank you. 

[Kurt_Bremser]

Please post example data in usable form, as shown here 

[Kurt_Bremser · Accepted solution]

The generic way to carry over is this:

data want;
set have;
retain _var1;
if var1 ne . /* if var1 is numeric, otherwise "" */
then _var1 = var1;
else var1 =_var1;
drop _var1;
run;

[Jack2012]

Perfect, that is what I want.