1# zydisney

如果可以确定顺序和原数据是一致的，使用

如果不确定，应使用by。

受用了，谢谢楼上二位

There are many ways to do the job. It depends your real situation to evaluate which one is better.

Proc append only appends one data set every time. If you really want to use it, you'd better to use SAS macros to repeat your sas codes. This is a case when you do some simulation jobs, etc.. Here is an example,

option mprint will print all generated SAS code in logs.

%macro loopit(n=10);
proc datasets lib=work;
delete all;
quit;

%do i = 1 %to &n;
    data new;
          dsn=&i;
          do j = 1 to 5;
             x=ranuni(990);
                 output;
          end;
        run;
             
        proc append base=all data=new; run;

        %end;
%mend;
options mprint;
%loopit(n=3)


if one has many small data sets with the same attribution then
data all;
   set w1 w2 w3 w4 w5 w6;
run;

Hope this helps.