What is the purpose of the IN operator in SAS?

The IN operator in SAS is used to specify multiple values in a WHERE clause or in a conditional statement. It allows you to check if a variable matches any value within a specified list of values. For example, using the IN operator can simplify the process of filtering data where you want to include multiple specific cases without having to write multiple OR conditions.

When you specify conditions using the IN operator, it checks if the variable's value appears in a defined set of values. This is particularly useful when you are dealing with categorical data and need to filter rows based on several categories at once. This functionality enhances code readability and maintainability by providing a more concise syntax compared to writing separate equality checks for each value.

The other options pertain to different functionalities in SAS: checking for an exact match refers to equality comparisons, combining datasets typically involves procedures like MERGE or SET, and assigning values to a variable usually involves using assignment statements with the SET or DATA step. None of these functions are related to the specific capability of the IN operator.