Step-by-Step Programming with Base SAS 9.4

Summary

Statements

IF condition THEN action;

<ELSE action>;

tests whether condition is true. If the condition is true, the action in the THEN clause is carried out. If condition is false and an ELSE statement is present, then the ELSE action is carried out. If condition is false and no ELSE statement is present, then the next statement in the DATA step is processed. Condition specifies one or more numeric or character comparisons. action must be an executable statement. That is, one that can be processed in an individual iteration of the DATA step. (Statements that affect the entire DATA step, such as LENGTH, are not executable.)

In SAS processing, any numeric value other than 0 or missing is true. The values 0 and missing are false. Therefore, ...