how to input data into a macro using SAS do loop? - sas

Question

I have the following macro that I have created and a dataset
%censusdata (districtname=,districtnum=);
data districtcodes;
input distnumber distname$;
cards;
1 Kaap/Cape
2 Simonstad
3 Bellville
4 Goodwood
5 Kuilsrivier
6 Wynberg
run;
Essentially I want to create a do loop which takes in distname from the districtcodes dataset and inputs it to distrctname in the %censusdata macro, and distnumber and inputs it to districtnum field in the macro.
How should I go about this?

Answer 1

Assuming you already have a macro developed, you can call it using CALL EXECUTE and the parameter values from the data set.
data districtcodes;
input distnumber distname$;
str=catt('%censusdata(districtname=', distname, ' , districtnum=', distnumber,
');');
call execute (str);
cards;
1 Kaap/Cape
2 Simonstad
3 Bellville
4 Goodwood
5 Kuilsrivier
6 Wynberg
;
;
;;
run;

Answer 2

As you discovered, DATA step datalines, (aka cards), are not compatible with the macro system.
You may want to rethink why the data has to be inside the macro. There are some use cases, but fewer than might seem at first.
Regardless of the reasoning here are a couple of ways (there are more)
place the data inside a DATA step string and parse it out using scan
place the data inside a macro variable and parse it out using %scan
create the data set prior to calling the macro and pass the data set name as well
Here is one using DATA step string parsing
%macro censusdata (districtname=,districtnum=);
data districtcodes (keep=dist:);
*input distnumber distname$;
*cards;
data = "
1 Kaap/Cape
2 Simonstad
3 Bellville
4 Goodwood
5 Kuilsrivier
6 Wynberg
";
put data=;
put data= $HEX60.;
do _n_ = 1 by 1 while (length(scan(data,_n_,' ')));
distnumber = input ( scan (data, _n_, ' '), best8. );
_n_ + 1;
districtname = scan (data, _n_, ' ');
output;
if _n_ > 10 then stop;
end;
stop;
run;
%mend;
%censusdata();
The macro example you show seems a little peculiar, as you are passing in parameters, ostensibly to help operate on some data, which is a static entity with respect to the macro.
As more reasonable approach might be to
eliminate the macro altogether
pass the name of the data set, and names of variables to be used for some code generation.
Such a macro would only make sense if you were performing identical types of processing on a wide range of data sets that meet an operant model (i.e. data set has at least two columns, one column for code numbers and the second for some associated text).
As you might see, coding macros with highly specific names and arguments (such as censusdata, districtname, districtcode) can be a wrapper with little re-use value.
data districtcodes;
input distnumber distname$;
cards;
1 Kaap/Cape
2 Simonstad
3 Bellville
4 Goodwood
5 Kuilsrivier
6 Wynberg
run;
Example invocation
%censusdata (data=districtcodes, codevar=distnumber, namevar=distname);
%mend;