if statement does not return the correct one

[fsuzhang]

the following simple script is supposed to output loannum, but it output state, I can not find where the logic is wrong.

%let loan_level_data_flag=1;

data _NULL_ ;

if &loan_level_data_flag. = 1 then

   do;

    %let by_option=loannum;

   end;

else if &loan_level_data_flag. ^= 1 then

   do;

    %let by_option=state;

end;

run;

%put &by_option.;

[novinosrin]

%let loan_level_data_flag=1;

data _NULL_ ;

if &loan_level_data_flag. = 1 then

   do;

    call symputx( 'by_option','loannum');

   end;

else if &loan_level_data_flag. ^= 1 then

   do;

   
    call symputx( 'by_option','state');

end;

run;

%put &by_option.;

[fsuzhang]

Thanks, your code works. what happened to my original code? I am curious.

[novinosrin · Accepted solution]

I'm afraid macro language %let is a compile time operation and so it executes before datastep execution begins, therefore What you need is an execution time operation, or in other words an interface to the macro facility to function at execution and create a macro variable during data step execution and the store the variable in a symbol table. CALL SYMPUTX does that.