如果该列变量全为缺失，删除这个变量

RT，变量可能为数值型或字符型，谢谢！data aaa;
input x y z$;
cards;
1 . .
2 . .
;
run;

判断y 和 z取值全为缺失后，删除y 和 z。

1. data aaa;
   
2.     input x y z$;
   
3.     cards;
   
4. 1 . .
   
5. 2 . .
   
6.     ;
   
7. run;
   
8. 
   
9. data _null_;
   
10.     set sashelp.vcolumn end=final;
    
11.     where memname="AAA";
    
12.     call symput("n"||strip(put(_n_,best.)),strip(name));
    
13.     if final then call symput("num",strip(put(_n_,best.)));
    
14. run;
    
15. 
    
16. %macro m1;
    
17. %do i=1 %to %eval(&num.);
    
18.     data _null_;
    
19.         set aaa end=final;
    
20.         if missing(&&n&i..) then _&&n&i..=0;
    
21.         else _&&n&i..=1;
    
22.         retain __&&n&i..;
    
23.         if _n_=1 then __&&n&i..=0;
    
24.         __&&n&i..=__&&n&i..+_&&n&i..;
    
25.         if final then call symput("check",strip(put(__&&n&i..,best.)));
    
26.     run;
    
27.     %if &check.=0 %then %do;
    
28.         data aaa;
    
29.             set aaa;
    
30.             drop &&n&i..;
    
31.         run;
    
32.     %end;
    
33. %end;
    
34. %mend m1;
    
35. %m1;

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1. data _null_;
   
2. set sashelp.vcolumn(keep=name libname memname) end=last;
   
3. where libname='WORK' and memname='AAA';
   
4. length code1 code2 $1000;
   
5. retain code2;
   
6. code1='data '||strip(name)||"; set aaa end=last;var="||quote(strip(name))||";if missing("||strip(name)||") then n+1;if last;keep var n;run;";
   
7. call execute(code1);
   
8. if _n_=1 then code2='data all;set '||strip(name);
   
9. else code2=strip(code2)||' '||strip(name);
   
10. if last then do;
    
11. code2=strip(code2)||';run;';
    
12. call execute(code2);
    
13. end;
    
14. run;
    
15. 
    
16. data _null_;
    
17. set aaa end=last;
    
18. if last then call symput('obs',cats(_n_));
    
19. run;
    
20. 
    
21. proc sql noprint;
    
22. select distinct var into: missvar separated by " "
    
23. from all
    
24. where n=&obs;
    
25. quit;
    
26. 
    
27. data wanted;
    
28. set aaa;
    
29. drop &missvar;
    
30. run;

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1. data a;
   
2. input x y z;
   
3. cards;
   
4. 1 . .
   
5. 2 . .
   
6. ;
   
7. run;
   
8. %macro test(work,data,want);
   
9. proc datasets lib=&work;
   
10. contents data=&data out=out;
    
11. quit;
    
12. proc sql;
    
13. select count(*) into:n from out;
    
14. select count(*) into:t from &data;
    
15. select name into:name1-:name%trim(%left(&n)) from out;
    
16. %do i=1 %to &n.;
    
17. select sum(missing(&&name&i.)) into:sum&i. from &data;
    
18. %end;
    
19. quit;
    
20. data &want;
    
21. set &data;
    
22. %do i=1 %to &n.;
    
23. %if %eval(&&sum&i.-&t.)=0  %then %do;
    
24. drop &&name&i.;
    
25. %end;
    
26. %end;
    
27. run;
    
28. %mend;
    
29. %test(work,a,want);

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感觉代码都很复杂啊！

如果仅是字符变量呢？

%let ds=work.aaa;
proc freq data=&ds nlevels;
   table _all_;
   ods output nlevels=nlevels(where=(nnonmisslevels>0));
run;

data _null_;
    set nlevels end=last;
        if _n_=1 then call execute("data &ds; set &ds; keep ");
                      call execute(tablevar);
        if last  then call execute(";run;");
run;

dxystata 发表于 2014-11-18 07:51
感觉代码都很复杂啊！

我的代码很简单的，而且对字符型和数值型都适用。

pobel 发表于 2014-11-18 14:05
%let ds=work.aaa;
proc freq data=&ds nlevels;
   table _all_;

这个好巧妙啊，赞一个