Hello all,
I currently have a data file looks like:
ID | Year | Var A |
1 | 2000 | 0 |
1 | 2001 | 0 |
1 | 2002 | 1 |
1 | 2003 | 0 |
2 | 2000 | 0 |
2 | 2001 | 1 |
2 | 2002 | 1 |
2 | 2003 | 1 |
2 | 2004 | 0 |
3 | 2001 | 0 |
3 | 2002 | 0 |
3 | 2003 | 1 |
3 | 2004 | 0 |
3 | 2005 | 1 |
3 | 2006 | 0 |
What I need is excluding observations with Var A = 0 prior to the first time when Var A = 1 by the group ID. So the outcome of the data needs to look like:
ID | Year | Var A |
1 | 2002 | 1 |
1 | 2003 | 0 |
2 | 2001 | 1 |
2 | 2002 | 1 |
2 | 2003 | 1 |
2 | 2004 | 0 |
3 | 2003 | 1 |
3 | 2004 | 0 |
3 | 2005 | 1 |
3 | 2006 | 0 |
How can I code it? Thank you.
data have;
input ID Year Var_A;
datalines;
1 2000 0
1 2001 0
1 2002 1
1 2003 0
2 2000 0
2 2001 1
2 2002 1
2 2003 1
2 2004 0
3 2001 0
3 2002 0
3 2003 1
3 2004 0
3 2005 1
3 2006 0
;
data want;
__k=0;
do until(last.id);
set have;
by id;
if Var_A=1 then __k=1;
if __k then output;
end;
drop _:;
run;
data have;
input ID Year Var_A;
datalines;
1 2000 0
1 2001 0
1 2002 1
1 2003 0
2 2000 0
2 2001 1
2 2002 1
2 2003 1
2 2004 0
3 2001 0
3 2002 0
3 2003 1
3 2004 0
3 2005 1
3 2006 0
;
data want;
__k=0;
do until(last.id);
set have;
by id;
if Var_A=1 then __k=1;
if __k then output;
end;
drop _:;
run;
Are you ready for the spotlight? We're accepting content ideas for SAS Innovate 2025 to be held May 6-9 in Orlando, FL. The call is open until September 25. Read more here about why you should contribute and what is in it for you!
Learn how use the CAT functions in SAS to join values from multiple variables into a single value.
Find more tutorials on the SAS Users YouTube channel.