SAS求子集

data subsets;
    array set1[*] $ a b c d e ('a', 'b', 'c', 'd', 'e');
    array set2[*] bin1-bin5;
    array set3[*] $ ele1-ele5;
    do i=0 to dim(set1)-1;
        set2(i+1)=2**(dim(set1)-(i+1));
    end;
    do j=0 to 2**dim(set1)-1;
        call missing(of ele:);
        do i=1 to dim(set1);
            if band(j, set2(i)) then set3(i)=set1(i);
        end;
        SUBSETS=cats(of ele:);
        keep SUBSETS;
        output;
    end;
run;