topic Re: Assign ID to pairs of consecutive rows in SAS Data Management

Assign ID to pairs of consecutive rows

STLT — Wed, 25 Jan 2017 06:04:24 GMT

Hi,

I have a dataset of individuals already sorted on a value. I would like to assign a pairID to the first two individuals, then the next pair, and so on. If the file contains an odd number of individuals, the last three are grouped to form a triplet. I hope that makes sense and would appreciate any tips.

Thanks!

HAVE	WANT
ID	ID	pairID
1	1	1
2	2	1
3	3	2
4	4	2
5	5	3
6	6	3
7	7	4
8	8	4
9	9	5
10	10	5
11	11	5

Re: Assign ID to pairs of consecutive rows

Reeza — Wed, 25 Jan 2017 06:16:24 GMT

Playing around with some basic math this is relatively straightforward.

Functions:

MOD()

Use NOBS option on SET statement to get the number of observations.

Use RETAIN

Data want;

set have NOBS=num end =eof;

RETAIN count;

If mod(_n_, 2) ne 0 and not eof then count+1;

run;

Re: Assign ID to pairs of consecutive rows

Haikuo — Wed, 25 Jan 2017 15:42:17 GMT

Of course I would choose to use @Reeza's solution myself, but FWIW, here is another approach outrageously not using MOD() ,

data want;
do _error_=1 to 2;
set sashelp.class end=last;
pairID=ifn(last and _error_=1,_n_-1,_n_);
output;
end;
run;

Re: Assign ID to pairs of consecutive rows

STLT — Mon, 30 Jan 2017 17:18:29 GMT

Thank you, both, for taking time to resolve this for me. I can't believe how few lines of codes are needed. I understand the logic, but am just not advanced enough to come up with it myself. Thanks again for the help!