Hi,
I would like to create the variable Z which takes the value 1 up until (and including when) Y=1 for the first time. After that, Z takes the value of 2.
For the same ID, Y can take the value of 1 at max two times.
Please see attached an example of what I need.
Thanks very much!
data have;
input ID ID_sub $ Y;* Z;
cards;
1 A 0 1
1 B 0 1
1 C 1 1
2 A 1 1
2 B 0 2
2 C 0 2
2 D 1 2
3 A 0 1
3 B 0 1
3 C 0 1
3 D 0 1
3 E 0 1
3 F 0 1
3 G 0 1
4 A 0 1
4 B 1 1
4 C 1 2
5 A 1 1
5 B 1 2
;
data want;
if 0 then set have;
z=1;
do until(last.id);
set have;
by id;
output;
if z<2 then z+y;
end;
run;
data have;
input ID ID_sub $ Y;* Z;
cards;
1 A 0 1
1 B 0 1
1 C 1 1
2 A 1 1
2 B 0 2
2 C 0 2
2 D 1 2
3 A 0 1
3 B 0 1
3 C 0 1
3 D 0 1
3 E 0 1
3 F 0 1
3 G 0 1
4 A 0 1
4 B 1 1
4 C 1 2
5 A 1 1
5 B 1 2
;
data want;
if 0 then set have;
z=1;
do until(last.id);
set have;
by id;
output;
if z<2 then z+y;
end;
run;
Thank you!!
Looks like a backtracking task. So, one approach is to read every group of records ending in Y=1 twice, initializing Z=0 at the beginning of each ID by-group and incrementing Z before each second pass:
data have ;
input ID ID_sub :$1. Y ;
cards ;
1 A 0
1 B 0
1 C 1
2 A 1
2 B 0
2 C 0
2 D 1
3 A 0
3 B 0
3 C 0
3 D 0
3 E 0
3 F 0
3 G 0
4 A 0
4 B 1
4 C 1
5 A 1
5 B 1
run ;
data want ;
do until (Y) ;
set have ;
by id ;
if first.id then Z = 0 ;
end ;
Z + 1 ;
do until (Y) ;
set have ;
output ;
end ;
run ;
Kind regards
Paul D.
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