Date:         Tue, 18 Jul 2000 20:53:29 GMT
Reply-To:     "John M. Wildenthal" <jmwildenthal@MY-DEJA.COM>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         "John M. Wildenthal" <jmwildenthal@MY-DEJA.COM>
Organization: Deja.com - Before you buy.
Subject:      Re: SAS: Iterative do loops with until statement

In article <00Jul18.152555edt.118081@gateway.viropharma.com>,
  "Hudson, Spencer" <shudson@VIROPHARMA.COM> wrote:
> Sometimes when you're not looking, the simple stuff comes and bites.
> In the following two steps, the first stops at n = 6, but the second
> continues to n=3. Can anyone tell me (a) why, and (b) can I mimic the
> first do loop using the syntax of the second. I ask this because my
> real specification list does not have even increments, so I cannot
> use the first syntax.
>
> Thanks,
> Spencer Hudson
>
> 308
> 309  data _null_;
> 310          flag = 0;
> 311          do n = 9 to 3 by -3 until (flag=1);
> 312                  if 7 >= n then flag = 1;
> 313                  put n= flag=;
> 314          end;
> 315          put n= flag=;
> 316  run;
>
> N=9 FLAG=0
> N=6 FLAG=1
> N=6 FLAG=1
> NOTE: The DATA statement used 0.01 seconds.
>
> 317
> 318  data _null_;
> 319          flag = 0;
> 320          do n = 9, 6, 3 until (flag=1);
> 321                  if 7 >= n then flag = 1;
> 322                  put n= flag=;
> 323          end;
> 324          put n= flag=;
> 325  run;
>
> N=9 FLAG=0
> N=6 FLAG=1
> N=3 FLAG=1
> N=3 FLAG=1

Since there is a variable assignment between the DO and UNTIL, it is an
iterative do loop, not a DO UNTIL do loop.

How are the arguments to n being passed?  An array or a macro variable
or hard coded?  Different methods of passing suggest different
solutions.


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