### Index Variables

The variable FOUND refers to the number of observations in the index. It is declared Read-Only of course. Its main use is either to write a SIC loop that goes through the index or to test for actions which should be performed only if something exists in the index. The FIND command does not return an error, but set FOUND = 0, if it finds nothing. A second variable related to the index is the INDEX array, of dimension FOUND, which contains the observation numbers of all observations in the index.