Step-by-Step Programming with Base SAS 9.4

Testing a Condition Before Creating an Observation

Sometimes you need to read a record, and hold that record in the input buffer while you test for a specified condition before a decision can be made about further processing. For example, the ability to hold a record so that you can read from it again, if necessary, is useful when you need to test for a condition before SAS creates an observation from a data record. To do this, you can use the trailing at-sign (@).

For example, to create a SAS data set that is a subset of a larger group of records, you might need to test for a condition to decide whether a particular record will be used to create an observation. The trailing at-sign placed before the semicolon at the end of an INPUT statement ...