filename f_list pipe "dir D:\three\dat /b";
data mylist;
infile f_list;
input file :$14.;
run;

data mylist;
  set mylist;
where file ? 'fit';
call symput('n',_n_);
put file _n_;
run;

%macro getn;
   data _null_;
      set mylist;
   %do i=1 %to &n.;
          if _n_=&i. then call symput("fn&i.",file);
 %end;
%mend;

%getn;

%macro inverse;
    
  %do i=1 %to &n.;
      data ex;
       infile "D:\three\dat\%CMPRES(&&fn&i.)" firstobs=2 ;
    input x y;
    run;

    ods listing close;
    ods output ParameterEstimates = paras ;
     proc nlin data=ex ;
     parms a=100  b=100 c=100  t2a=10 t2b=10 t2c=10   e=10;
     model y=a*exp(-x/t2a)+b*exp(-x/t2b)+c*exp(-x/t2c)+e;
    run;
    ods listing;

          data inver (keep= name parameter estimate);
               set paras;
      name=scan("&&fn&i.",1);
      run;
                      
    proc append base=inversx data=inver ;                                           
    run;
       %end;
%mend;

%inverse

proc sort data=inversx;
by  name;
run;
 proc transpose data=inversx out=final (drop=_name_);
  var  estimate ;
  id parameter;
  by name;
run;
proc print data=final ;
run;

求教程序解释。谢谢！