Hi Everyone:
I posted below an example data set along with a column that I would like to create. In this data set, I have different people (personid) and for some observations, an event is present (1) and for some it is not (0). The data are sorted by personid and date, which I did not show. I want to create a new column (want):
-whenever, event=0, it should be 0.
-for a given personid: for the first event=1, it should be 1, and should stay as 1 as long as event=1.
-for a given personid: each time, the event transitions from 0 to 1, its value increases by 1.
I do not know how exactly I should go about this. I would very much appreciate your help.
Thank you
personid event want
1 0 0
1 0 0
1 0 0
1 0 0
1 0 0
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
1 0 0
1 0 0
1 1 2
1 1 2
1 1 2
1 0 0
1 1 3
2 1 1
2 1 1
2 0 0
2 0 0
2 0 0
2 0 0
2 1 2
2 1 2
2 1 2
2 0 0
2 0 0
2 1 3
2 1 3
2 1 3
2 0 0
2 1 4
The following will do what you want:
data want (drop=_:); set have; by personid; _last_event=ifn(not first.personid,lag(event),0); if first.personid then _hold=0; if event eq 1 and _last_event eq 0 then _hold+1; want=ifn(event eq 0,0,_hold); run;
Art, CEO, AnalystFinder.com
The following will do what you want:
data want (drop=_:); set have; by personid; _last_event=ifn(not first.personid,lag(event),0); if first.personid then _hold=0; if event eq 1 and _last_event eq 0 then _hold+1; want=ifn(event eq 0,0,_hold); run;
Art, CEO, AnalystFinder.com
One possibility:
data want;
set have;
by personid event notsorted;
if first.personid then event_counter=0;
if first.event and event=1 then event_counter + 1;
if event=0 then want=0;
else want = event_counter;
drop event_counter;
run;
Thank you so much for your help! I love this forum.
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