是不是这样？

data ex;
input x1-x5;
cards;
1 2 3 4 5
6 7 8 9 10
;
run;

data ex1;
set ex;
array   m(5)  x1-x5;
array n(10);
sum=0;
do i=1 to dim(m)-1;
    if i ne 1 then  sum+(dim(m)-i+1);
    do j=i to dim(m)-1;
        if (m(i)+m(j+1))=0 then
    n(sum+j-i+1)=.;
        else
        n(sum+j-i+1)=(m(i)-m(j+1))/(m(i)+m(j+1));
end;
end;
run;

65   data test;
66       y=1000;
67           array x[200] x1-x200;
68           do _n_=1 to 200;
69              x(_n_)=_n_;
70           end;
71   run;

NOTE: The data set WORK.TEST has 1 observations and 201 variables.
NOTE: DATA statement used (Total process time):
      real time           0.00 seconds
      cpu time            0.00 seconds


72
73   data test1;
74       set test;
75           array x(200);
76           array nn(19900) ;
77           do i=1 to 199;
78             do j=i+1 to 200;
79            num+1;
80                    nn(num)=(x(i)-x(j))/(x(i)+x(j));
81             end;
82           end;
83           keep y nn:;
                    --
                    241
ERROR 241-185: The array nn is not allowed in a DROP/KEEP/RENAME context.

84   run;

NOTE: The SAS System stopped processing this step because of errors.
WARNING: The data set WORK.TEST1 may be incomplete.  When this step was stopped there were 0
         observations and 19901 variables.
WARNING: Data set WORK.TEST1 was not replaced because this step was stopped.
NOTE: DATA statement used (Total process time):
      real time           0.06 seconds
      cpu time            0.04 seconds

数据未能读入进去。。如上所示： there were 0
         observations and 19901 variables.

40   data test;
41       y=1000;
42           array x[200] x1-x200;
43           do _n_=1 to 200;
44              x(_n_)=_n_;
45           end;
46   run;

NOTE: The data set WORK.TEST has 1 observations and 201 variables.
NOTE: DATA statement used (Total process time):
      real time           0.02 seconds
      cpu time            0.00 seconds


47
48   data test1;
49       set test;
50           array x(200);
51           array nn(19900) ;
52           do i=1 to 199;
53             do j=i+1 to 200;
54                   num+1;
55                    nn(num)=(x(i)-x(j))/(x(i)+x(j));
56             end;
57           end;
58           keep y nn:;
59   run;

NOTE: There were 1 observations read from the data set WORK.TEST.
NOTE: The data set WORK.TEST1 has 1 observations and 19901 variables.
NOTE: DATA statement used (Total process time):
      real time           0.09 seconds
      cpu time            0.07 seconds

您好，谢谢您的耐心帮助，但是我的程序还是老是在nn上面出错，我用SAS9.0 ,是不是我支持nn:的用法？如下：

219          keep y nn:;
                    --
                    241
ERROR 241-185: The array nn is not allowed in a DROP/KEEP/RENAME context.

220  run;
怎么办啊？本人对循环是不太懂。。谢谢您的回复