目前我用的是：%if "%upcase(%scan(&a,&i,%str( )))" eq "T"

请问有更直接的办法么？

从15行开始才是正点！

indexw function is the one I'm looking for, thank you.

By the way, do you know how can identify sevel cases like :

%let a= tt cc fdx d x e r t s d ;
%let b = t d s;

I'm sorry, I omit the same order with &b and &c.

If there is more than one case, you can try %do loop
or %if .. %then
      %do;
        ...;
      %end;
    %else %then %do; ... %end;