sas - Flagging the first instance in an episode without transposing -

i'm working in sas , i'm trying create column disease_flag flags first row given disease code occurs in array. in case disease code care 'a36'. ideally without first transposing.

so data looks this:

 episode_id diagcode1 diagcode2 diagcode3          121       a36       b11         121       a36       b11       b12           121       b12       b05       b06          122       b12         122       a36       b12       b13          122       b12       b01         123       b12       b13       b11           123       b12       a36         123       b13       b12 

i want add additional column called disease_flag flags first instance of a36 in array of columns diagcode1--diagcode3.

thus final output this:

episode_id diagcode1 diagcode2 diagcode3 disease_flag        121       a36       b11                    1        121       a36       b11       b12          0        121       b12       b05       b06          0        122       b12                              0        122       a36       b12       b13          1        122       b12       b01                    0        123       b12       b13       b11          0        123       b12       a36                    1        123       b13       b12                    0 

you can using retained helper variable resets 0 each id , stays set 1 first time a36 found:

data have; input episode_id diagcode1 $ diagcode2 $ diagcode3 $; infile cards missover; cards;         121       a36       b11         121       a36       b11       b12           121       b12       b05       b06          122       b12         122       a36       b12       b13          122       b12       b01         123       b12       b13       b11           123       b12       a36         123       b13       b12 ; run;  data want;     set have;     episode_id;     retain t_flag;     if first.episode_id t_flag = 0;     disease_flag = (diagcode1 = 'a36' or diagcode2 = 'a36' or diagcode3 = 'a36') , t_flag = 0;     if disease_flag t_flag = 1;     drop t_flag; run;