Assign unique id

[heretolearn]

Hi all,

I have a dataset in which I need to assign a unique id by two variables.

Below is what I have:

id      reg_seq

1       1

1       1

1       2

1       3

2       1

2       2

2       2

This is what I want:

id      reg_seq       seq

1       1                  1

1       1                  1

1       2                  2

1       3                  3

2       1                  4

2       2                  5

2       2                  5

Any advice?

Thanks!

[Astounding · Accepted solution]

Assuming your data set is sorted so that the BY statement works:

data want;

set have;

by id reg_seq;

if first.reg_seq then seq + 1;

run;

[heretolearn]

Thank you, both!

[KentaMURANAKA]

Hi, heretolearn:

If you know First (or Last) By Variables & Retain Statement, you can get your objective submitting this code.

data test;
    input id reg_seq;
    datalines;
    1 1
    1 1
    1 2
    1 3
    2 1
    2 2
    2 2
    ;
run;
proc sort data=test out=test_1;
    by id reg_seq;
run;
data test_2;
    set test_1;
    retain seq;
    by id reg_seq;
    if first.reg_seq eq 1 then byflg=1;
    if _n_ eq 1 then seq=0;
    if byflg ne . then seq+byflg; 
run;