what does this code mean?

[HJ_]

I am trying to match two groups. And I have a question about this statement. 

what does this code mean? 

data matched&n.; set matched&n._1-matched&n._&i.; proc sort data=matched&n.; by aID; run;

the bolded part!

Thank you so much!

[PeterClemmensen · Accepted solution]

Hi @HJ_ and welcome to the SAS Community 🙂

I'm guessing that the macro variables &n and &i confuses you. The code in cold simply means that the data step reads all the data sets matched&n._1 to matched&n._i. If &n=1 and &i=3, then that means that three data sets are read. Like below

%let n=1;
%let i=3;

data matched1_1;a=1;run;
data matched1_2;a=2;run;
data matched1_3;a=3;run;

data matched&n.;
    set matched&n._1-matched&n._&i.;
run;

Hope this helps. Otherwise, feel free to ask.