first.statements with multiple variables

[sophia_SAS]

Haikuo,

Say I did want to now have Var_b_2 as another level so now my final dataset looks like the below set.  How do you adjust your code for the additional level?

               Var_a               Var_b       Var_b_2    Var_C

          0          1     1         1    

          0          1     2         1

          0          2     1         1

          0          3     1         1

          0          3     5         1

          0          3     6         1

          1          2     1         2

          1          3     1         2

          2          3     1         3

          3          3     2         1

          3          3     5         2

          4          1     1         2

          4          1     2         2

          4          2     1         3

          4          3     5         3

[Tom · Accepted solution]

It looks to me like you just want to sort by var b and b2 and reset the counter when you see FIRST.B2.  Var_A is just an example of an extra variable that you want to carry along.  You can extent this logic to as many sort by variables as you want, you still just want to trigger the counter off of the change in the last variable in the list.

%let byvars=var_b var_b2;

proc sort data=have;

  by &byvars;

run;

data want;

  set have ;

  by &byvars;

  if first.%scan(&byvars,-1) then var_c=1;

  else var_c+1;

run;

Obs    var_a    var_b    var_b2    want_c    var_c

  1      0        1         1         1        1

  2      4        1         1         2        2

  3      0        1         2         1        1

  4      4        1         2         2        2

  5      0        2         1         1        1

  6      1        2         1         2        2

  7      4        2         1         3        3

  8      0        3         1         1        1

  9      1        3         1         2        2

10      2        3         1         3        3

11      3        3         2         1        1

12      0        3         5         1        1

13      3        3         5         2        2

14      4        3         5         3        3

15      0        3         6         1        1

[sophia_SAS]

Thanks Tom!  This worked!

[Haikuo]

Hi,

Var_a               Var_b       Var_b_2    Var_C

          0          1     1         1    

          0          1     2         1

          0          2     1         1

          0          3     1         1

          0          3     5         1

          0          3     6         1

          1          2     1         2

          1          3     1         2

          2          3     1         3

          3          3     2         1

          3          3     5         2

          4          1     1         2

          4          1     2         2

          4          2     1         3

          4          3     5         3

I am still confused about your rules, so before I am doing anything useless, please explain those three rows. How var_c values that way.

Haikuo

[Haikuo]

Ok,

data have;

input Var_a Var_b;

cards;

          0          1

          0          2

          0          3

          1          2

          1          3

          2          3

          3          3

          4          1

          4          2

          4          3

;

data want;

array t(3) _temporary_;

  set have;

    do _n_=1 to dim(t);

    t(_n_)+(var_b=_n_);

    end;

    var_c=t(var_b);

run;

proc print;run;

Haikuo

update: using '_n_' to replace 'i'

[Ksharp]

I coded it a few days ago for another user.

data have;
input Var_a Var_b;
cards;
          0          1
          0          2
          0          3
          1          2
          1          3
          2          3
          3          3
          4          1
          4          2
          4          3
;
run;
data want;
if _n_ eq 1 then do;
 declare hash ha();
  ha.definekey('var_b');
  ha.definedata('count');
  ha.definedone();
 end;
 set have;
 if ha.find()=0 then do; count+1;ha.replace();end;
  else do;count=1;ha.replace();end;
run;

KSharp