macro function to use in data step

[KoVa]

Hi guys,

I want to create a macro function that I can use in a data step. 

it checks the value of variable1 (langa), which in the tables I use always is a char variable ('1','2'). 

if the value is = '2' then the outcome of the function should be a concatenation of 'OPTN_' and whatever value is in variable2(date_). if not, then it should be 'OPTF_'||var2. 

here is what I have so far (I used do steps since I plan on adding some stuff there later)

*rsubmit;
%macro ts_date_nice(langa, date_);
%if &langa = '2' %then
%do;
     %let dn = 'OPTN_'||&date_;
%end;
%else
%do;
     %let dn = 'OPTF_'||&date_;
%end;
&dn;
%mend ts_date_nice;

i tried it like this on a test table:

BROLNG       ACT_PRD

2                    NLB

1                    NLC

data check;
set testtbl;
daten = %ts_date_nice (BROLNG,ACT_PRD);
run;

result of the new variable daten is however

OPTF__NLB

OPTF__NLC

so the concatenation works, but there is something wrong with the if statement?

I have tried without the '' (so just %if &langa = 2) but that didn't change anything. also ran it on other tables, same result. 

[Kurt_Bremser · Accepted solution]

The macro processor is a code generator and does its work before the resulting code is handed off to the base SAS interpreter.

To do what you want, macro language is useless. What you want is a data step custom function created with PROC FCMP.

[KoVa]

thanks!