Making groups for different outcomes

[rookie21]

yes, suppose, a patient had five operation with the types being the one u stated:
1->2->1->3->2

Then it should come out as an option 1->2->1->3->2, as Im interested in all changes

[PaigeMiller · Accepted solution]

data want;
    set have;
    length group $ 256;
    array lead lead:;
    group=cats(lead(1));
    do i=2 to dim(lead);
        if lead(i)^=lead(i-1) then do;
            group=cats(group,'->',lead(i));
        end;
    end;
    drop i;
run;

[rookie21]

This did help. 

Thank you so much !