Date:         Tue, 21 Mar 2006 12:01:34 -0800
Reply-To:     "Choate, Paul@DDS" <pchoate@DDS.CA.GOV>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         "Choate, Paul@DDS" <pchoate@DDS.CA.GOV>
Subject:      Re: Comparison in IF clause
Comments: To: Gerhard Hellriegel <ghellrieg@T-ONLINE.DE>
Content-Type: text/plain; charset="US-ASCII"

Hi Gerhard - interesting stuff - I'd be tempted to express it as
"mod(i,32)<16" as in:

data a;
  do i=0 to 255;
     x= mod(i,32)<16;
     put i= x=;
  end;
run;


But the bit mask _is_ quicker. Try this:

data a;
  do i=0 to 1e7;
     x=(i='...0....'b);
  end;
run;

data a;
  do i=0 to 1e7;
     x= mod(I,32)<16;
  end;
run;


hth

Paul Choate
DDS Data Extraction
(916) 654-2160

> -----Original Message-----
> From: SAS(r) Discussion [mailto:SAS-L@LISTSERV.UGA.EDU] On Behalf Of
> Gerhard Hellriegel
> Sent: Tuesday, March 21, 2006 10:11 AM
> To: SAS-L@LISTSERV.UGA.EDU
> Subject: Re: Comparison in IF clause
>
> That makes a binary compare.
> If you have a decimal 2, the binary representation in the length of 8
bit
> is
>
> '00000010'b
>
> means:
>
> 0*2**7 + 0*2**6 + .... + 1*2**1 + 0*2**0
>
> In that way you can represent numbers from 0 to 255
>
> The comparison you mention now means:
>
> all numbers which have the 5th bit (from the right side) as "0" are
equal.
> E.g. '000000000', but also '111101111'b
>
> by the way: you have 9 digits, that's unusual. Maybe you mean 8, but 9
or
> more is also ok.
>
> That is a very strong feature. Note the results of that little
program:
>
> data a;
>   do i=0 to 255;
>     x=(i='...0....'b);
>     put i= x=;
>   end;
> run;
>
> You see, that you can also get the same result with comparing
decimals,
> but
> which are selected in:
>
> if i="...0...."b;
>
> thats a very elegant way to write:
>
> if i in (0,1,2,3,4,5,6,7,8,9....,15,32,33,34,...); or something like
>
>   if 0<=i<=15 or 32<=i<=47 or ...;
>
>
>
>
>
>
>
> On Tue, 21 Mar 2006 05:56:17 -0800, ssb <mail_ssb@YAHOO.COM> wrote:
>
> >Hello,
> >
> >Am new to SAS programming and this may be too elementary for some
> >people. Suppose, MY_VARIABLE is a field of input record layout and
its
> >size is 1 byte.
> >
> >What does the following comparison statement do exactly...? Is the
> >right side of the comparison-equation in form of packed / zoned /
> >binary data...?
> >
> >IF MY_VARIABLE = '....0....' B
> >
> >Thanks for your help.