topic Re: Do loops in SAS Enterprise Guide

Do loops

Lupacante — Wed, 07 May 2014 08:21:28 GMT

Hi all,

I would like to have something like this:

do i=1 to 12;

month&i = 5 + i - 1;

output;

end;

which should make the variables

month1 = 5

month2 = 6

...

month12 = 16

However, writing month&i doesn't work.

Any ideas?

Thanks in advance,

Marco

Re: Do loops

RW9 — Wed, 07 May 2014 08:32:55 GMT

Hi,

The & (ampersand) is for macro processing. The easiest way to change it to use & is to wrap a macro around it:

%tmp ();

data a;

%do I=1 %to 10;

b=&I.;

%end;

run;

%mend tmp()

%tmp;

However I am not saying that is the best solution or the way to go, only answering the specific item. If I wanted to do this type of thing then I would generate the code:

data _null_;

call execute('data want;');

do i=1 to 12;

call execute('month'||strip(put(I,best.))||'=5+'||strip(put(I,best.))||'-1;

output;');

end;

call execute('run;');

run;

This will generate a dataset with the 12 month statements and execute it.

Re: Do loops

Kurt_Bremser — Wed, 07 May 2014 08:48:08 GMT

Try this:

data want;

.....

array months{*} month1 - month12;

do i = 1 to 12;

months{i} = 5 + i - 1;

end;

...

drop i;

run;

Re: Do loops

Lupacante — Wed, 07 May 2014 09:05:31 GMT

Thanks, that works.

Now I would like to make variables month1 - month12 available for use later in the code. I've come up with this, which works:

call symputx('month1',month1);

call symputx('month2',month2);

...

call symputx('month12',month12);

But is there any way to put that as a loop?

Thanks

Re: Do loops

RW9 — Wed, 07 May 2014 09:14:07 GMT

Yes, with KurtBremsers code you can just put the call symputx after the months{I} statement. However, this goes back to my post and generating the code. Why go to all the bother of creating macro varibles when you can just expand the code generator to generate the later code you also need, e.g. if I want to create a dataset with the month name:

data _null_;

do i=1 to 12;

call execute('data month'||strip(put(5+I,best.))||';

do some other code;

run;');

end;

run;

You really see the benefits on large programs, when all the generator needs is some parameterization.

Re: Do loops

Lupacante — Wed, 07 May 2014 09:20:14 GMT

How, just by adding

call symputx('months(i)',months(i);

Ok, I'll look into the call execute function, thanks again.

Re: Do loops

RW9 — Wed, 07 May 2014 09:24:17 GMT

Been a while since I use symput but:

call symput('months'||strip(put(I,best.)),months{I});

You need to use curly braces for arrays. I hope the concatenation works in symput like that :smileyshocked:)

Re: Do loops

Kurt_Bremser — Wed, 07 May 2014 09:45:22 GMT

Just add

call symput('month'!!strip(put(i,best.)),strip(put(months{i},best.)));

in the loop.

I just added some small things to RW9's suggestion to avoid NOTE's in the log and any unwanted blanks in the macro vars.