SAS executes one DATA or PROC step at a time. To do this, it needs to determine when one step ends and the next one begins. Most of the time, a RUN; statement tells SAS that the current step is complete. However, a CARDS; statement also has that purpose within a DATA step. It tells SAS that it already has all the statements that are part of the DATA step, and that the data to read in will follow.
... View more
