Post test data in the form of a datastep!!!
What is NA, is it one variable, a set of variables? If it is one variable, why is it one variable, a variable is to hold one piece of information, hence coding against a variable with multiple pieces of information will be difficult, whereas if each their own its very simple.
data want; na1="a1"; na2="b1"; na3="c1"; na4="a2"; original_na=catx(" ",of na:); call sortc(of na:); run;
Do you mean this:
proc sort data=have (rename=(NA=NA1)) out=int ; by NA1; run; data want; merge have int ; run;