An efficient way to Copying values in subsequent records - SAS

Question

I have a dataset that is grouped by category variables in the source data. For example:

Bar  | Foo1
     | Foo2
     | Foo3
Bar2 | Foo4
     | Foo5
     | Fo         


        

Answer 1

You can retain the non-missing value and apply it to any missing values, e.g.

data want ;
  set have ;

  length last $10. ;
  retain last '' ;

  if not missing(PARENT) then last = PARENT ;
  else PARENT = last ;

  drop last ;
run ;