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Date:         Tue, 10 Nov 1998 11:41:08 -0500
Reply-To:     WHITLOI1 <WHITLOI1@WESTAT.COM>
Sender:       "SAS(r) Discussion" <SAS-L@UGA.CC.UGA.EDU>
From:         WHITLOI1 <WHITLOI1@WESTAT.COM>
Subject:      Re: Can do this by 'one step' ?
Comments: To: Chenglong Han <hanc@CALIB.COM>
Content-Type: text/plain; charset=US-ASCII

Subject: Can do this by 'one step' ? Summary: In one macro invocation, yes. A simple and then a user friendly solution is given. Respondent: Ian Whitlock <whitloi1@westat.com>

Chenglong Han <hanc@CALIB.COM> asks:

> I want to invoke a sas macro, for example, MABC, for multiple > times. Can I do this just by invoking once ? For example, > > %MACRO MABC ( VAR); ....... %MEND; > > Instead of doing this by %MABC ( X1); %MABC (X2); ....... %MABC > (Xn); > > Can I do this by some way like %MABC (X1-XN);

One, could easily achieve the objective by changing the parameter list. For example:

%macro mabc ( var= ) ; %put macro mabc exectuing with var=&var ; %mend mabc ;

%macro drvrmabc ( root= , strt= , stop= ) ; %local i ;

%if %quote(&stop) = %str() %then %let stop = &strt ; %do i = &strt %to &stop ; %mabc ( var = &root&i ) %end ; %mend drvrmabc ;

%drvrmabc ( root=xyz12a, strt=43 ) %drvrmabc ( root=xyz12a, strt=43, stop=45 )

Of course, one could replace the call to %MABC in the macro DRVRMABC with the code of MABC and then change the name of the macro to MABC, if desired. Note DRVRMABC is callable anywhere MABC is.

I interpreted the question as a more interesting one. Can one preserve the parameter and notation as asked for? Again I have used a separate driving macro and a key word parameter. (I don't write macros with positional parameters except in unusual circumstances.) Here is the code. It demonstrates a big advantage given by the ability to execute DATA step functions within macro.

%macro drvrmabc ( var= x1 - x5 ) ; %local temp strt stop root1 root2 i x ; %let temp = %scan(&var, 1 , - ) ; %let temp = %sysfunc(reverse(&temp)) ; %let x = %sysfunc(verify(&temp,0123456789)) ; %let strt = %sysfunc(reverse(%substr(&temp,1,&x-1))) ; %let root1 = %sysfunc(reverse(%substr(&temp,&x))) ;

%let temp = %scan(&var, 2 , - ) ; %if %quote(&temp) = %str() %then %do ; %let stop = &strt ; %let root2 = &root1 ; %end ; %else %do ; %let temp = %sysfunc(reverse(&temp)) ; %let x = %sysfunc(verify(&temp,0123456789)) ; %let stop = %sysfunc(reverse(%substr(&temp,1,&x-1))) ; %let root2 = %sysfunc(reverse(%substr(&temp,&x))) ; %end ;

%if &root1 = &root2 and &strt <= &stop %then %do ; %do i = &strt %to &stop ; %mabc ( var = &root1&i ) %end ; %end ; %else %do ; %put ERROR(drvr): Cannot parse, halting. VAR=&var ; %end;

%mend drvrmabc ;

%drvrmabc ( var=xyz12a43 ) %drvrmabc ( var=xyz12a43-xyz12a45 ) %drvrmabc ( var=xyz12a43-xy12a45 )

Again the driving macro may be called anywhere the original macro can be called. The code is a good deal harder, but this is the price of friendliness.

None of the above assumes one is in a DATA step and VAR names a variable or group of variables in a SAS data set. If this is the case then one could have the driver

%macro drvrmabc ( data = &syslast , var=a -- b c1 - c5 d ) ;

The code for the driver now gets a good deal more difficult to do correctly, and I will not present it. However, I am interested in pursuing the question of whether the parameter DATA can be eliminated. Does anyone know of a method of finding out what data sets have been opened in compiling a DATA step so that the DATA parameter would be superfluous? Then, of course, I would also like access to the PDV, but I am certain this is not yet possible.

Ian Whitlock


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