topic create a flag for first non-zero observation by group in SAS Data Management

create a flag for first non-zero observation by group

vannestelrooy — Thu, 14 Apr 2016 02:38:01 GMT

Hi, I am not sure if this question has been asked, and I am new to SAS, so any help would be appriciated.

I have a table like the following:

ID Value

1 0

1 100

1 200

1 0

2 0

2 100

2 0

3 0

3 100

3 200

And I would like to create a flag for the first non-zero values for each ID. The resulting table will be:

ID Value Flag

1 0 0

1 100 1

1 200 0

1 0 0

2 0 0

2 100 1

2 0 0

3 0 0

3 100 1

3 200 0

Note that the observations are already sorted by ID and then Date, so I don't want to change the order of the observations. Is there any easier way to do this? Thank you so much!

Re: create a flag for first non-zero observation by group

Ksharp — Thu, 14 Apr 2016 02:52:51 GMT

data have;
input ID Value;
cards;
1       0
1       100
1       200
1       0
2       0
2       0
2       0
2       100
2       0
3       0
3       100
3       200
;
run;
data want;
 set have;
 by id;
 if first.id then n=0;
 if value ne 0 then n+1;
 flag=ifn(n=1 and value ne 0,1,0);
 drop n;
run;

Re: create a flag for first non-zero observation by group

vannestelrooy — Thu, 14 Apr 2016 03:09:30 GMT

Thank you! never used ifn function before!