data two;

y='2';

run;

%let x=10;

%let var=y;

data one;

set two (keep=&var);

z=&var*&x;

run;

which one of the following is the value of the variable Z when the progeam finishes execution?

A.ERROR

B.20(as a numeric)

C.20(as a character)

D. .(missing numeric)

Answer: B

我只晓得macro variable 应该都是character, 但是macro variable进行运算时会自动从character transfer to numeric?

请高手帮忙解读为什么答案是B.3xxxx