What if I want it the following way?

Thanks,

1       2       7
2       3     5.5
3       2.5     4

5# bobguy
功底确实很深厚
谢谢

To use the row mean:
data test;
input x1-x3;
array x{*} x1-x3;
mean = mean(of x1-x3);
do i = 1 to dim(x);
  if x[i]=. then x[i]=mean;
end;
drop mean i;
datalines;
1 2 7
2 3 .
3 . 4
;
proc print;run;

To use the column mean;
data test;
input x1-x3;
datalines;
1 2 7
2 3 .
3 . 4
;
proc means noprint;
output out=test2(drop=_type_ _freq_)
       mean(x1 x2 x3) = d1 d2 d3 ;
data final;
merge test test2;
array x{*} x1-x3;
array d{*} d1-d3;
array dd{*} dd1-dd3;
retain dd1 dd2 dd3;
do i = 1 to 3;
if d[i]~=. then dd[i]=d[i];
   else dd[i] =dd[i];
if x[i] = . then x[i]=dd[i];
end;
drop d1-d3 dd1-dd3 i;

proc print; run;