Using Data Set Inside Do Loops

[Junyong]

Hi, I want to ask if this is possible.

data DataSet;
	call streaminit(1);
	do Set=1 to 3;
		do Number=1 to 10;
			Variable=rand("normal");
			output;
		end;
	end;
run;

proc iml;
	do IMLSet=1 to 3;
		use DataSet(where=(Set=IMLSet));
			read all var{Variable};
		close DataSet;
	end;
quit;

In this case, DataSet contains Variable, which is indexed by both Set and Number. In IML, I intended to load DataSet Set by Set so used a loop with an IML variable IMLSet, but this does not work since the "where" only uses the variables in DataSet and it does not have IMLSet there. Alternatives are welcome.

[Ksharp]

data DataSet;
	call streaminit(1);
	do Set=1 to 3;
		do Number=1 to 10;
			Variable=rand("normal");
			output;
		end;
	end;
run;

proc iml;
use dataset;
read all var{set};
close;
level=unique(set);
do i=1 to ncol(level);
  use dataset;
  read all var _all_ into x where (set=(level[i]));
  print x;
  close;
end;
quit;

P.S. If you really want learn IML code, I really suggest you to read Rick's blog .You can find most answer of IML in it .

[Rick_SAS · Accepted solution]

KSharp's solution is good. To read more about how to use the WHERE clause with dynamic values that change in a loop. See

"The WHERE clause in SAS/IML"

The only improvement I'd suggest to KSharp's code is to put the USE and CLOSE statements outside the DO loop. There is no need to open/close the data set multiple times. You can apply his solution to the OP's original attempt, as follows:

proc iml;
use DataSet;
	do IMLSet=1 to 3;
		read all var{Variable} where(Set=(IMLSet));
      print Variable;
	end;
close DataSet;
quit;

[Ksharp]

Yeah. I know what Rick mean. So here is the code revisited.

data DataSet;
	call streaminit(1);
	do Set=1 to 3;
		do Number=1 to 10;
			Variable=rand("normal");
			output;
		end;
	end;
run;

proc iml;
use dataset;

read all var{set};
level=unique(set);
do i=1 to ncol(level);
  read all var _all_ into x where (set=(level[i]));
  print x;
end;

close;
quit;