谢谢vvvvvvvvvvvvvvvvvvvvvvv

再强调一下，9.13及以前的版本貌似只能用宏……

非常感谢    但是  %let a3=%scan(&var_list,&y," ");
                                %if &y.~=&i. & &y.~=&j. %then %do;
                                        a&x.=&a3.;;  是想做什么啊  ，大概什么一种思路呢  ，能否帮忙解释下

还有怎么把他们的变量名也保持原来的

到底要的是什么。。
不是说变量名要a1-a6么？怎么又要原来的，保持原来的变量名那就简单多了

Here i give a simpler solution which uses comb and allcomb routine to generate all data sets with keep option.

278  data _null_;
279    file 'c:\temp\8s6.sas';
280    array x(8) $1 ('a' 'b' 'c' 'd' 'e' 'f' 'g' 'h');
281     k=6;
282     n=dim(x);
283     nsets=comb(n, k);
284     do j=1 to nsets;
285        call allcomb(j, k, of x[*]);
286        put 'temp'  j '(keep=' x1-x6 ')';
287     end;
288  run;

NOTE: The file 'c:\temp\8s6.sas' is:
      Filename=c:\temp\8s6.sas,
      RECFM=V,LRECL=32767,File Size (bytes)=0,
      Last Modified=03Aug2014:20:47:08,
      Create Time=03Aug2014:20:45:47

NOTE: 28 records were written to the file 'c:\temp\8s6.sas'.
      The minimum record length was 25.
      The maximum record length was 26.
NOTE: DATA statement used (Total process time):
      real time           0.02 seconds
      cpu time            0.03 seconds


289
290  options source2;
291
292  data %include 'c:\temp\8s6.sas';
NOTE: %INCLUDE (level 1) file c:\temp\8s6.sas is file c:\temp\8s6.sas.
293 +temp1 (keep=a b c d e f )
294 +temp2 (keep=a b c d e h )
295 +temp3 (keep=a b c d e g )
296 +temp4 (keep=a b c d f g )
297 +temp5 (keep=a b c d f h )
298 +temp6 (keep=a b c d g h )
299 +temp7 (keep=a b c e g h )
300 +temp8 (keep=a b c e g f )
301 +temp9 (keep=a b c e h f )
302 +temp10 (keep=a b c g h f )
303 +temp11 (keep=a b d g h f )
304 +temp12 (keep=a b d g h e )
305 +temp13 (keep=a b d g f e )
306 +temp14 (keep=a b d h f e )
307 +temp15 (keep=a b g h f e )
308 +temp16 (keep=a c g h f e )
309 +temp17 (keep=a c g h f d )
310 +temp18 (keep=a c g h e d )
311 +temp19 (keep=a c g f e d )
312 +temp20 (keep=a c h f e d )
313 +temp21 (keep=a g h f e d )
314 +temp22 (keep=b g h f e d )
315 +temp23 (keep=b g h f e c )
316 +temp24 (keep=b g h f d c )
317 +temp25 (keep=b g h e d c )
318 +temp26 (keep=b g f e d c )
319 +temp27 (keep=b h f e d c )
320 +temp28 (keep=g h f e d c )
NOTE: %INCLUDE (level 1) ending.
321     ;
322     set a;
323  run;

NOTE: There were 3 observations read from the data set WORK.A.
NOTE: The data set WORK.TEMP1 has 3 observations and 6 variables.
NOTE: The data set WORK.TEMP2 has 3 observations and 6 variables.
NOTE: The data set WORK.TEMP3 has 3 observations and 6 variables.
NOTE: The data set WORK.TEMP4 has 3 observations and 6 variables.
NOTE: The data set WORK.TEMP5 has 3 observations and 6 variables.
NOTE: The data set WORK.TEMP6 has 3 observations and 6 variables.
NOTE: The data set WORK.TEMP7 has 3 observations and 6 variables.
NOTE: The data set WORK.TEMP8 has 3 observations and 6 variables.
NOTE: The data set WORK.TEMP9 has 3 observations and 6 variables.
NOTE: The data set WORK.TEMP10 has 3 observations and 6 variables.
NOTE: The data set WORK.TEMP11 has 3 observations and 6 variables.
NOTE: The data set WORK.TEMP12 has 3 observations and 6 variables.
NOTE: The data set WORK.TEMP13 has 3 observations and 6 variables.
NOTE: The data set WORK.TEMP14 has 3 observations and 6 variables.
NOTE: The data set WORK.TEMP15 has 3 observations and 6 variables.
NOTE: The data set WORK.TEMP16 has 3 observations and 6 variables.
NOTE: The data set WORK.TEMP17 has 3 observations and 6 variables.
NOTE: The data set WORK.TEMP18 has 3 observations and 6 variables.
NOTE: The data set WORK.TEMP19 has 3 observations and 6 variables.
NOTE: The data set WORK.TEMP20 has 3 observations and 6 variables.
NOTE: The data set WORK.TEMP21 has 3 observations and 6 variables.
NOTE: The data set WORK.TEMP22 has 3 observations and 6 variables.
NOTE: The data set WORK.TEMP23 has 3 observations and 6 variables.
NOTE: The data set WORK.TEMP24 has 3 observations and 6 variables.
NOTE: The data set WORK.TEMP25 has 3 observations and 6 variables.
NOTE: The data set WORK.TEMP26 has 3 observations and 6 variables.
NOTE: The data set WORK.TEMP27 has 3 observations and 6 variables.
NOTE: The data set WORK.TEMP28 has 3 observations and 6 variables.
NOTE: DATA statement used (Total process time):
      real time           0.50 seconds
      cpu time            0.21 seconds

恩，从8个变量中抽取任意的6个，并保持原来的变量名

不好意思   ，  如果test是一下的样子  ，该怎样写
data test;
input a b c d e f g h;
cards;
1 2 3 5 9 7 4 2
5 8 6 9 7 2 0 3
run;

Here is the program.

Input data set a with variables a b c d e f g h.


data a;
        input a b c d e f g h;
        cards;
        10 20 30 40 50 60 70 80
        11 21 31 41 51 61 71 81
        12 22 32 42 52 62 72 82
        ;
run;

proc print;run;

data _null_;
  file 'c:\temp\8s6.sas';
  array x(8) $1 ('a' 'b' 'c' 'd' 'e' 'f' 'g' 'h');
   k=6;
   n=dim(x);
   nsets=comb(n, k);
   do j=1 to nsets;
      call allcomb(j, k, of x

);
      put 'temp'  j '(keep=' x1-x6 ')';
   end;
run;

options source2;

data %include 'c:\temp\8s6.sas';
   ;
   set a;
run;

8s6.sas 是什么   我运行后出来这个界面

you need make a directory under c: namely c:\temp

您好，不好意思，在这个问题的基础上再请教一下，如果此时增加了i j k,三个变量 ，在每个数据集中仍然只是选择a b c d e f g h 中的6个变量，并保持i j k 三个变量，请问程序该如何改写。非常感谢。数据变成这个样

data a;
        input a b c d e f g h i j k;
        cards;
        10 20 30 40 50 60 70 80 1 2 3
        11 21 31 41 51 61 71 81 1 2 3
        12 22 32 42 52 62 72 82 3 4 6
        ;
run;

Here it is.  

  data _null_;
    file 'c:\temp\11s6.sas';
    array x(11) $1 ('a' 'b' 'c' 'd' 'e' 'f' 'g' 'h', 'i','j','k');
     k=6;
     n=dim(x);
     nsets=comb(n, k);
     do j=1 to nsets;
        call allcomb(j, k, of x(*));
        put 'temp'  j '(keep=' x1-x6 ')';
     end;
  run;

  data %include 'c:\temp\11s6.sas';
  ;
    set a;
  run;

不好意思，可能我没有说明白，我的意思是，每个数据集中都有i,j,k这三个变量，其他六个变量还是在a,b,c,d,e,f,g,h中选择，也就是说每个数据集有9个变量，但是i,j,k始终占有3个。最后的生成数据集个数还是与先前一样的，而不是像11选6那样几百个。
谢谢

data _null_;
    file 'c:\temp\8s6.sas';
    array x(8) $1 ('a' 'b' 'c' 'd' 'e' 'f' 'g' 'h');
     k=6;
     n=dim(x);
     nsets=comb(n, k);
     do j=1 to nsets;
        call allcomb(j, k, of x(*));
        put 'temp'  j '(keep=' x1-x6 'i j k)';
     end;
  run;

  data %include 'c:\temp\8s6.sas';
  ;
    set a;
  run;