topic Re: How to keep first 2 obs conditioned upon 2 variables? in SAS Data Management

How to keep first 2 obs conditioned upon 2 variables?

jlajla — Wed, 03 Feb 2016 23:58:01 GMT

Hello, how would I keep the first two observations conditioned upon it being the first observation of 2 variables?

For example, I have:

ID Year Month Time

1 95 1 1

1 95 1 2

1 95 1 3

1 95 2 1

1 95 2 2

1 95 2 3

1 95 2 4

1 96 3 1

1 96 3 2

1 96 3 3

And need:

ID Year Month Time

1 95 1 1

1 95 1 2

1 95 2 1

1 95 2 2

1 96 3 1

1 96 3 2

I've found how this can be achieved conditional upon the first 2 observations of one variable:

data top2(drop=count);
  set groups;
  by group descending amount;
  if first.group then count=0;
  count+1;
  if count le 2 then output;
run;

But I can't seem to find out how to do it conditioned upon the first 2 observations of 2 variables. I've tried adding a second first.var, but this doesn't seem to work.

I'm using SAS Studio. Thank you.

Re: How to keep first 2 obs conditioned upon 2 variables?

Ksharp — Thu, 04 Feb 2016 00:52:33 GMT

Your code looks good . just change a little thing.

data top2(drop=count);
  set groups;
  by ID  Year Month;
  if first.Month then count=0;
  count+1;
  if count le 2 then output;
run;

Re: How to keep first 2 obs conditioned upon 2 variables?

Jagadishkatam — Thu, 04 Feb 2016 03:05:08 GMT

You may also try the proc sql method

proc sort data=have;
by id year month time;
run;

proc sql;
create table test(where=(s<=2)) as select *, (monotonic()-min(monotonic())+1) as s from have
group by id,year,month
order by id, year, month,time  ;
quit;

Re: How to keep first 2 obs conditioned upon 2 variables?

jlajla — Thu, 04 Feb 2016 18:06:43 GMT

exactly what i needed, thank you!

Re: How to keep first 2 obs conditioned upon 2 variables?

jlajla — Thu, 04 Feb 2016 18:07:05 GMT

this works too, thank you!