topic Re: Array help in SAS Programming

Array help

div44 — Sun, 23 Oct 2016 06:12:50 GMT

Hello,

I am stuck at where I need to find the ith observation which is equal to the ith observation + 90. For example if my i=1 value is 2, then I need to find m?, where the value would be 2+90 = 92.

I am using this code.

data x;

set y;

array help(*) 1-370;

do i = 1 to 370;

do m = 1 to 370;

if help(i) + 90 = help(m) then leave;

end;

run;

Thank you

Re: Array help

Reeza — Sun, 23 Oct 2016 06:29:06 GMT

You don't need two loops.

Can you have multiple matches?

The WHICHN function can return the index of an array that contains the value you're looking for.

Do i = 1 to 370;

x=whichnhelpv(I)+ 90, of help(*));

if x>0 then leave;

end;

Re: Array help

Shmuel — Sun, 23 Oct 2016 08:59:36 GMT

It seems like a typo defining: array help(*) 1-370;

You probably meant, something like: array help(*) v1-v370;

@Reeza you meant to write (missed open bracket):

x=whichn( helpv(I)+ 90, of help(*) );

Re: Array help

Reeza — Sun, 23 Oct 2016 09:29:39 GMT

@Shmuel Eagle eyes! Thanks!

Do i =1 to 370;
X = whichn(help(I) + 90, of help(*));
If x > 0 then leave;
End;

Re: Array help

div44 — Sun, 23 Oct 2016 15:37:51 GMT

Thank you so much for the help. The codes worked, however I want x-i to be less than 180. If x-i crosses 180 then I would want to select that value of i which would give me x-i<180.

Thanks once again

Re: Array help

Reeza — Sun, 23 Oct 2016 16:41:56 GMT

Please illustrate your problem with sample data amd expected output.

If you have any other restrictions make sure to highlight them.

Re: Array help

div44 — Mon, 24 Oct 2016 15:05:17 GMT

Please find a sample dataset

It is a dataset of students and their attendance, which is cumulative over 12 days. I need to find the earliest day when their attendance crossed 5 days over a period of 7 days. Thank you

ID	Day1	Day2	Day3	Day4	Day5	Day6	Day7	Day8	Day9	Day10	Day11	Day12
Robin	1	2	3	4	5	6	7	8	9	10	11	12
Michael	1	2	2	3	4	5	5	6	7	8	9	10
Jeremy	1	2	3	3	4	5	6	6	7	7	7	7
Matt	1	1	1	2	2	3	3	3	4	4	5	6
Sara	1	2	3	4	5	5	5	6	6	7	8	9
Tony	1	2	2	2	2	3	3	3	4	4	4	4

Re: Array help

Reeza — Mon, 24 Oct 2016 16:53:09 GMT

What is the expected output for data?

Re: Array help

div44 — Mon, 24 Oct 2016 17:03:53 GMT

Expected output

Name Start_day Day_crossing_5

Robin 1 5

Michael 1 6

Jeremy 1 6

Matt 5 12

Sara 1 5

Tony . .

It does not need to be the first day, if using the first day at start_date does not give the answer, then I want the program to move to the next one. In this way the start_day for Matt reached 5, because on day12 his value was 5 greater than the value(2) on day5. So over a period of 7days he crossed 5 attendace units. If you would have used day1 as start date for Matt, he would have reached only 3 by day 7. Does that help ?

Thanks,

Divyan

Re: Array help

Shmuel — Mon, 24 Oct 2016 20:34:16 GMT

You are posting a very similar situation to your previous question.

Here is @Reeza's solution addapted to your last post:

array dayx day1-day12;
Do i =1 to 12;
X = whichn(dayx(I) > 5 , of dayx(*));
If x > 0 then leave;
End;

Re: Array help

div44 — Mon, 24 Oct 2016 23:29:32 GMT

Thank you for the answer, but then how would I restrict my lookup period to 7 days. I do not want to include any observations if they occur after 7 days.

Re: Array help

Shmuel — Tue, 25 Oct 2016 00:52:06 GMT

I'm not sure I understand what you mean.

Anyhow, you can filter the output by adding a line after END of the DO loop, like:

IF i > 7 then delete;