%macro test ;
%let trt_1 = 12 ;
%let i = 2 ;
%put &&trt_%eval(&i.-1) ;
%put a=&trt_1 ;
%mend ;
%test;
log:
WARNING: Apparent symbolic reference TRT_ not resolved.SYMBOLGEN: Macro variable I resolves to 2&trt_1SYMBOLGEN: Macro variable TRT_1 resolves to 12a=12
要第一个解析出来。