Hands-On SAS for Data Analysis

Indexing

As the name suggests, indexing is a way to tell SAS how things have been arranged. Typically, the SAS dataset is stored in pages. There is no way for SAS to know on which page or sequence the information is stored unless the dataset is indexed. The index stores values in ascending value order for a specific variable or variables and includes information as to the location of those values within observations in the data file. In other words, an index allows you to locate an observation by value.

Indexes can be done on one variable or multiple variables. If done on multiple variables, they are called composite indexes. Indexes needed to be stored somewhere for the subsequent programs using the indexed data to be able to leverage ...