Date:         Tue, 29 Apr 2008 05:13:37 -0700
Reply-To:     Peter <crawfordsoftware@GMAIL.COM>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         Peter <crawfordsoftware@GMAIL.COM>
Organization: http://groups.google.com
Subject:      Re: Check if a column exists in a dataset?
Comments: To: sas-l@uga.edu
Content-Type: text/plain; charset=ISO-8859-1

On Apr 29, 11:38 am, RolandRB <rolandbe...@hotmail.com> wrote:
> On Apr 29, 11:30 am, Eversmann <rifazraz...@gmail.com> wrote:
>
> > Hi,
>
> > I am designing a generic macro --- to do some processing on a given
> > dataset.
>
> > And a perticular column (say X) doesn't always exist.
>
> > is there a way to check if this column exist and do the processing
> > accordingly...
>
> > Many thanks in advance
>
> There are various ways of doing this. One of the simplest is using the
> sashelp.vcolumn view.

I presume you need a macro that returns tru/false (1/0) without going
through the statement boundary (let alone the step boundary)
open()
  returns dsID
varnum()
  returns 0 if varname is not in dsID
Culling from the manual and placing in a macro that returns a
variable's VARNUM

To demonstrate useage, here is a log from which you can parse the
macro.
Notice that the variable name search performed by the varnum()
function is not case-sensitive

 3          %macro myVarN( var, data= &syslast )
 4                       / des= 'return VARNUM for a varname in
&data';
 5            %local dsid rc vnum;
 6            %let vnum = 0;
 7            %let dsid=%sysfunc(open(&data,is));
 8            %if &dsid > 0 %then %do;
 9               %let Vnum=%sysfunc(varnum(&dsid,&var));
 10              %let rc = %sysfunc(close(&dsid));
 11           %end;
 12         &Vnum
 13         %mend  myVarN ;
 15         %put >>%myVarN( aGe, data= sashelp.class )<< ;
 >>3<<
 16         option _last_ = sashelp.class ; * and using default
"latest" dataset;
 17         %put >>%myVarN( aGe)<< >>%myVarN( seX )<< ;
 >>3<< >>2<<

PeterC