data test;
   array x x1-x8;
     do  i= 1 to 8;
     seed = 1000+i;
     x(i) = int(rannor(seed)*10);
     end;
   drop seed i;
run;

data result;
  array x x1-x8;
  set test;
  positive_sum=0;
  negative_sum=0;
  do i = 1 to dim(x);
       if x(i) >0 then  positive_sum + x(i);  
       if x(i) <0 then  negative_sum + x(i);  
  end;
  drop i;
run;

谢谢，学习了。

加个虚拟变量，指定变量大于0则等于1，否则等于0
然后用proc means求sum的时候加个by变量就好了

I wish there were a sumif function too.
if just summing up by +/-, no new dummy variables necessary
To do it in PROC MEANS, define a format firstThe same can be accomplished in PROC SQL with 'GROUP BY sign(x)', where x is the variable to be tallied.

谢谢！之前一直对数组操作不熟悉啊:P