To get obs number of a dataset

There are some approaches to get observation number of a dataset.

I usually use the observation numbers to decide how to generate a TLG. For example, if there is no data, I would generate a table with text as “No observation found…”, instead of no output or a blank page.

Mostly, I would use following codes:

%LET dsid =%sysfunc(OPEN(dataset_name));
%LET nobs =%sysfunc(ATTRN(&dsid, NLOBS));
%LET rc =%sysfunc(CLOSE(&dsid));

It should be good enough for me, because I know the dataset will be there. This means, above codes will not work for SAS views or if a dataset does not exist. If I want to put above codes in more general programs, I may check &dsid if the dataset exists.

I can also use SASHELP.VTABLE to fetch dataset information I want. It usually consumes a little more brain energy to get there, for example, I have to deal more details on libname and memname, and maybe more keystrokes.

If I want to know the observation numbers of subset of a dataset, which means a dataset with WHERE statement, it seems that I have to count the observations one by one. Usually, I use following codes:

%LET nobs=0;

DATA _null_;

    SET dataset_name (WHERE=(where_statement)) end=eof;

    IF eof THEN CALL SYMPUTX("nobs",_n_);

RUN;

It is important to have "%let nobs=0;" to initiate macro variable nobs.