topic Re: Nested DO Loop in SAS Studio

Nested DO Loop

marianhabesland — Thu, 19 Oct 2017 16:05:42 GMT

I am trying to make a DO Loop that does two things:

1) Create a variable called Mouse ID that repeats the values 1-15, which each value being repeated 8 times.

2) Create a variable called Day, so basically DO Day = 0 TO 28 BY 4. The issue is also getting this repeated for all the 15 mice.

The output should start like this, and at the end produce output with 120 variables.

Mouse ID Day

1 0

1 4

1 8

1 12

1 16

1 20

1 24

1 28

2 0

2 4

.....

How do I make this DO Loop for this?

This is what I started with, but need ideas for how to get everything repeated an appropriate number of times

data WORK.Illus;
do MouseID = 1 to 15;
do Day = 0 to 28 by 4;
output;
end;
end;
run;

Re: Nested DO Loop

Reeza — Thu, 19 Oct 2017 16:11:29 GMT

That looks right, I think you need another DO loop for the 8 records though, but I'm not sure what you want as a final structure so that will tell you were to put the 8 loop. I think it likely goes in between your current loops.

data WORK.Illus;
	do MouseID = 1 to 15;
		do Rep = 1 to 8;
			do Day = 0 to 28 by 4;
				output;
			end;
		end;
	end;
run;

Re: Nested DO Loop

marianhabesland — Thu, 19 Oct 2017 16:17:51 GMT

Thanks for your answer! So that repeats the Day how I was thinking. The issue is that it repeats the Mouse ID from 1-8, each eight times and then starts repeating from 1 again. I need the variable 1-15 to each repeat eight times. Do I need another repeat statement somewhere?

Re: Nested DO Loop

marianhabesland — Thu, 19 Oct 2017 16:20:54 GMT

	MouseID	Day
1	1	0
2	1	4
3	1	8
4	1	12
…	…	…
118	15	20
119	15	24
120	15	28

This table shows the end of the output as well as it is supposed to look

Re: Nested DO Loop

Reeza — Thu, 19 Oct 2017 16:25:14 GMT

15 Mouse * 8 repititions is 120, but your code already does that....

You can add the 1 to 120 by adding in a counter if you want.

data WORK.Illus;
	N=0;

	do MouseID = 1 to 15;
			do Day = 0 to 28 by 4;
				N+1;
				output;
			end;
	end;
run;

Re: Nested DO Loop

marianhabesland — Thu, 19 Oct 2017 16:28:58 GMT

Ok, yeah that works. I think the issue was the repeat statement. It kept repeating from 1 to 8 rather than 1 to 15, so when I removed that it worked. Thanks!