Hi all,
I would like to remove a group of observations from my dataset if the first value does not meet a certain criteria. For example, I would like to delete all entries for a certain subject ID when the first QC value is 0. If the first QC value is 1, then I do not want to delete any entries from this subject ID.
Here is an example of what my data looks like (envision additional columns with various outcome variables):
ID QC
1 1
1 0
1 1
1 1
2 0
2 0
2 1
2 1
3 1
3 0
3 1
I would like achieve the following:
ID QC
1 1
1 0
1 1
1 1
3 1
3 0
3 1
*subject with ID=2 was deleted because the first observation did not meet quality control (QC=0).
Thanks in advance!
data have;
input ID QC ;
cards;
1 1
1 0
1 1
1 1
2 0
2 0
2 1
2 1
3 1
3 0
3 1
;
data want;
set have;
by id;
retain flag;
if first.id then call missing(flag);
if first.id and qc=1 then flag=1;
if flag;
drop flag;
run;
data have;
input ID QC ;
cards;
1 1
1 0
1 1
1 1
2 0
2 0
2 1
2 1
3 1
3 0
3 1
;
data want;
set have;
by id;
retain flag;
if first.id then call missing(flag);
if first.id and qc=1 then flag=1;
if flag;
drop flag;
run;
Thanks so much!
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