topic Re: Consecutive Numbers in SAS Programming

Consecutive Numbers

Geo- — Mon, 10 Sep 2018 09:19:53 GMT

to find all numbers that appear at least three times consecutively with data step.

data have;input Id num ;
cards;
1 1
2 1
3 1
4 2
5 1
6 2
7 2

;

Id	Num
1	1
2	1
3	1
4	2
5	1
6	2
7	2

+-----------------+For example, given the above Logs table, 1 is the only number that appears consecutively for at least three times.

| ConsecutiveNums |
+-----------------+
| 1               |
+-----------------+

Re: Consecutive Numbers

RW9 — Mon, 10 Sep 2018 09:08:20 GMT

Please once again, refer to how to post a question help. Post test data in the form of a datstep!

As such:

if lag2(num)=num and lag(num)=num then output;

May work, nothing to test it on as not going to type in test data.

Re: Consecutive Numbers

Geo- — Mon, 10 Sep 2018 09:54:05 GMT

Sir,have updated as what you mentioned.

Re: Consecutive Numbers

RW9 — Mon, 10 Sep 2018 09:57:53 GMT

Thanks, and I have just tested and appears to work for the given test data:

data have;
  input id num;
cards;
1 1
2 1
3 1
4 2
5 1
6 2
7 2
;
run;

data want (drop=id);
  set have;
  if lag2(num)=num and lag(num)=num then output;
run;

Re: Consecutive Numbers

Astounding — Mon, 10 Sep 2018 11:34:19 GMT

While it works for this test data, it does have a flaw. If the same number appears 5 times in a row, it will output that number 3 times instead of once. Here's an alternative:

data want;

count=0;

do until (last.num);

set have;

by num notsorted;

count + 1;

end;

if count >= 3;

keep num count;

run;