options

    mprintsymbolgen mlogic

      ;

%macro ransample_data(dsin,dsout,Replacement,SampleSize);

%if %upcase("&Replacement")="YES"  %then %do;

%*creating random sample with replacement;

   data &dsout(drop=i);

    do i=1to &SampleSize;

        PickIt=ceil(ranuni(123)*TotObs);

        ObsPicked=PickIt;

        set &dsin point=PickIt   nobs=TotObs;

        output;

      end;

      stop;

 run;

%end;

%else  %if %upcase("&Replacement")="NO"  %then %do;

%* create random sample without replacement;

  data &dsout(drop=SampleSize ObsLeft);

         SampleSize=&SampleSize;

         ObsLeft=TotObs;

         do while(SampleSize>0and ObsLeft>0) ;

           PickIt+1;

         if ranuni(123)<SampleSize/ObsLeft then

           do;

                ObsPicked=PickIt;

                set &dsin point=PickIt nobs=TotObs;

                output;

                SampleSize=SampleSize-1;

               end;

              ObsLeft=ObsLeft-1;

            end;

     stop;

run;

%end;

%else  %putERROR:Replacement shout be  yes or no ;

 %mendransample_data;

 %ransample_data(sashelp.class, class_data_rep,yes,10);

 %ransample_data(sashelp.class, class_data_norep,no,10);

  %ransample_data(sashelp.class, class_data_norep,whatever,10);

2.用proc serveyselect 实现

%macro ransample_proc(dsin,dsout,Replacement,SampleSize);

%if %upcase("&Replacement")="YES"  %then %do;

  proc surveyselect data=&dsin out=&dsout method=urs  n=&SampleSize;

  run;

%end;

%else %if %upcase("&Replacement")="NO"  %then %do;

 proc surveyselect data=&dsin out=&dsout method=srs  n=&SampleSize;

 run;

%end;

%else %put ERROR: Replacement shout be  yes or no ;

%mendransample_proc;

%ransample_proc(sashelp.class,class_proc_rep,yes,10);

%ransample_proc(sashelp.class,class_proc_norep,no,10);

%ransample_proc(sashelp.class,class_proc_norep,whatever,10);