Date:         Wed, 3 May 2000 16:54:32 -0500
Reply-To:     Daryl Travnicek <dat@UNLSERVE.UNL.EDU>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         Daryl Travnicek <dat@UNLSERVE.UNL.EDU>
Subject:      Re: Macro Loop - General
Content-Type: text/plain; charset="us-ascii"

Ian - I read your posting regarding the general macro loop with interest &
wondered if the &cond variable was necessary - I have included sample code
at bottom of this post.  Am I missing something?

Daryl

/*
------------------------------

Date:    Wed, 3 May 2000 09:49:46 -0700
From:    Jean-Pierre Le Cruguel <lecruguel@EPID.JGH.MCGILL.CA>
Subject: Re: Use of %eval and/or %sysevalf

Thanks a lot Ian and others who contributed.
I needed a very general macro, to work with any value, and any increment.
I just adapted it to play with 3 inner loops, it works great.

Those interested can contact me to get the code.

JP

----- Original Message -----
From: "WHITLOI1" <WHITLOI1@westat.com>
To: "JP" <lecruguel@EPID.JGH.MCGILL.CA>; <SAS-L@LISTSERV.UGA.EDU>; "Poul
Ravn Sorensen" <poulravn1@hotmail.com>
Sent: Tuesday, May 02, 2000 10:29 AM
Subject: Re[2]: Use of %eval and/or %sysevalf


> JP,
>
> Loops with noninteger by values are notorious.  With that said, here is
code.
>
> %macro loop ( start = 0.1 , stop = 2 , by = 0.1 ) ;
>    %local f_x ;
>
>     %if %sysevalf(&by > 0) %then %let cond = %nrstr(&f_x <= &stop) ;
>     %else
>     %if %sysevalf(&by < 0) %then %let cond = %nrstr(&f_x >= &stop) ;
>    %else
>        %let cond = 0 ;
>
>     %let f_x = &start ;
>    %DO %while ( %sysevalf(%unquote(&cond)) ) ;
>         %put f_x=&f_x ;
>         %let f_x = %sysevalf(&f_x + &by ) ;
>    %end ;
> %mend  loop ;
>
> %loop(start=0.1,stop=2.0,by=.1)
>
> Ian Whitlock <whitloi1@westat.com>
>
> ____________________Reply Separator____________________
> Subject:    Re: Use of %eval and/or %sysevalf
> Author: JP <R_E_M_O_V_E_lecruguel@EPID.JGH.MCGILL.CA>
> Date:       5/2/2000 4:47 PM
>
> Hi all,
>
> Sorry Poul, I do not have answers, but I have a similar question.
> I would like to use some non integer macro variables: ex:
> %DO f_x = 0.1 %TO 2 %BY 0.1;
> ...
> Is there an "official" way to do that? I succeeded once with EVAL (using a
> x10 factor) but I need something more robust.
>
> Any idea?
> I am going to check sysevalf.
>
> JP
>
> "Poul Ravn Sorensen" <poulravn1@hotmail.com> wrote in message
> news:8emh34$q9o$1@news1.tele.dk...
> > Hi people,
> >
> > I haven't used the EVAL macro function a lot but am a bit confused. My
old
> > well-worn manuals (v5) mention the use of %EVAL to do simple arithmetics
> on
> > macro variables. Whereas this works in a simpl example I could not get
it
> to
> > work in a more complex case. Search in the help files (v.6.12) gives
> nothing
> > on %EVAL; instead %SYSEVALF is found.
> >
> > Now my question is: Do I use %EVAL or %SYSEVALF in v.6.12?
> >
> > I can forward examples, but for now the answer to this will be helpfull
> >
> > Thanks in advance
> >
> > Poul Ravn Sorensen
> > Copehagen
> > Denmark
> >
> >

------------------------------
*/


 %macro loop ( start = 0.1 , stop = 2 , by = 0.1 ) ;
    %local f_x ;

     %if %sysevalf(&by > 0) %then %let cond = %nrstr(&f_x <= &stop) ;
     %else
     %if %sysevalf(&by < 0) %then %let cond = %nrstr(&f_x >= &stop) ;
    %else
        %let cond = 0 ;

     %let f_x = &start ;
    %DO %while ( %sysevalf(%unquote(&cond)) ) ;
         %put f_x=&f_x ;
         %let f_x = %sysevalf(&f_x + &by ) ;
    %end ;
 %mend  loop ;

 %loop(start=0.1,stop=2.0,by=.1)

*------------------------------------------------------------------;
*            DT - my humble attempt...
*------------------------------------------------------------------;
%macro loop1 ( start = 0.1 , stop = 2 , by = 0.1 ) ;
  %local g_x n_x ;

  %Let n_x = %SysEvalf((&stop-&start)/&by+1) ;
  %Put n_x = &n_x   by = &by;

  %Do i = 1 %to &n_x;
    %Let g_x = %SysEvalf(&start+(&i-1)*&by);
    %Put g_x = &g_x;
  %End;
%mend  loop1 ;

%loop1(start=0.01,stop=2.0,by=.01) ;
%loop1;
*------------------------------------------------------------------;


-------------------------
Daryl Travnicek
SAS Programmer / Biometry
103e Miller Hall
Lincoln, NE  68583-0712
- - - - - - - - - - - - -
dat@unlserve.unl.edu
(402) 472-4746
-------------------------