Date: Wed, 19 Aug 2009 08:27:53 -0500
Reply-To: "Data _null_;" <iebupdte@GMAIL.COM>
Sender: "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From: "Data _null_;" <iebupdte@GMAIL.COM>
Subject: Re: The SUM statement (was: Deleting columns)
In-Reply-To: <FEE685C811A7E44AAD17E47B2A966E29A858674CA1@KITE.wharton.upenn.edu>
Content-Type: text/plain; charset=ISO-8859-1
I don't get that result. I get the expected(documented) result with
no message. Version 9.1.3.
1255 data _null_;
1256 put x=;
1257 x + (2*x);
1258 run;
x=0
On 8/19/09, Keintz, H. Mark <mkeintz@wharton.upenn.edu> wrote:
> Art et. al.:
>
> There IS documentation. The page http://support.sas.com/documentation/cdl/en/lrdict/61724/HTML/default/a000289454.htm (titled "SUM statement") literally says that
>
> x+(expression);
>
> is equivalent to
>
> retain variable 0;
> variable=sum(variable,expression);
>
>
> But that is not always true, as is shown by the sas note produced by:
>
> data _null_;
> x+(2*x);
> run;
>
> NOTE: Missing values were generated as a result of performing an operation on missing values.
> Each place is given by: (Number of times) at (Line):(Column).
>
>
> The sum statement appears to actually be equivalent to:
>
> retain variable .; /** NOT ZERO **/
> variable=sum(variable,expression);
>
> Of course, the above is effectively the same as "retain variable 0" as long as "expression" does not involve the summing variable.
>
> Regards,
> Mark
>
>
>
> > -----Original Message-----
> > From: SAS(r) Discussion [mailto:SAS-L@LISTSERV.UGA.EDU] On Behalf Of
> > Arthur Tabachneck
> > Sent: Sunday, August 16, 2009 9:24 AM
> > To: SAS-L@LISTSERV.UGA.EDU
> > Subject: Re: Deleting columns
> >
> > Nat,
> >
> > While Palapara was correct, I'm not sure that I've ever read that using
> > the
> > x+1 rather than =x+1 syntax both retains the variable AND initializes
> > it to
> > zero. Of course, from the example it obviously does, but I didn't know
> > that.
> >
> > Of course, as shown below, using the =x+1 requires x to be initialized
> > in
> > order to achieve the desired results.
> >
> > DATA one;
> > input X;
> > retain Y ;
> > if mod( x, 3 ) = 1 then y=y + 1;
> > cards;
> > 1
> > 2
> > 3
> > 4
> > 5
> > 6
> > 7
> > 8
> > 9
> > ;
> > proc print data = one ;
> > run;
> >
> > DATA one;
> > input X;
> > retain Y 0 ;
> > if mod( x, 3 ) = 1 then y=y + 1;
> > cards;
> > 1
> > 2
> > 3
> > 4
> > 5
> > 6
> > 7
> > 8
> > 9
> > ;
> > proc print data = one ;
> > run;
> >
> > Art
> > ---------
> > On Sun, 16 Aug 2009 09:02:01 -0400, Nathaniel Wooding
> > <nathaniel.wooding@DOM.COM> wrote:
> >
> > >Palapara
> > >
> > >You are quite right. When I wrote this, I was thinking that I needed
> > to
> > initialize Y to 0 but the code
> > >
> > >Data ;
> > >Retain y 0;
> > >X+1;
> > >Y+1;
> > >Run;
> > >
> > >disproves this. I used Retain since that is a simple way to initialize
> > a
> > value when one actually needs to initialize it.
> > >
> > >Nat Wooding
> > >
> > >-----Original Message-----
> > >From: SAS(r) Discussion [mailto:SAS-L@LISTSERV.UGA.EDU] On Behalf Of
> > palapara
> > >Sent: Friday, August 14, 2009 7:07 PM
> > >To: SAS-L@LISTSERV.UGA.EDU
> > >Subject: Re: Deleting columns
> > >
> > >I think "retain Y 0 ;" this command could be omitted, since y+1 means
> > >y is retained automatically.
> > >
> > >
> > >On Aug 14, 2:10 pm, nathaniel.wood...@DOM.COM (Nathaniel Wooding)
> > >wrote:
> > >> I looked a second time at your post. A simpler approach is
> > >>
> > >> DATA one;
> > >> input X;
> > >>
> > >> retain Y 0 ;
> > >> if mod( x, 3 ) = 1 then y + 1;
> > >> cards;
> > >> 1
> > >> 2
> > >> 3
> > >> 4
> > >> 5
> > >> 6
> > >> 7
> > >> 8
> > >> 9
> > >> run;
> > >> proc print data = one ;
> > >> run;
> > >>
> > >> -----Original Message-----
> > >> From: SAS(r) Discussion [mailto:SA...@LISTSERV.UGA.EDU] On Behalf Of
> > Nickname unavailable
> > >> Sent: Friday, August 14, 2009 1:35 PM
> > >> To: SA...@LISTSERV.UGA.EDU
> > >> Subject: Re: Deleting columns
> > >>
> > >> I have a variable that is a simple count variable. like this.
> > >>
> > >> X
> > >> 1
> > >> 2
> > >> 3
> > >> 4
> > >> 5
> > >> 6
> > >> 7
> > >> 8
> > >> 9
> > >>
> > >> I would like to create another variable Y that looks something like
> > >> this. Every 3 observations has a single value starting from the
> > value
> > >> of 1.
> > >>
> > >> X Y
> > >> 1 1
> > >> 2 1
> > >> 3 1
> > >> 4 2
> > >> 5 2
> > >> 6 2
> > >> 7 3
> > >> 8 3
> > >> 9 3
> > >>
> > >> and so on. Anyone has an idea? Would greatly appreciate it.
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> > >does not in any case represent a firm ENERGY COMMODITY bid or offer
> > >relating thereto which binds the sender without an additional
> > >express written confirmation to that effect. The information is
> > >intended solely for the individual or entity named above and access
> > >by anyone else is unauthorized. If you are not the intended
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