IsIn
Purpose
Looks to see if the first parameter is identical to any other parameter(s) in
a list.
Arguments
IsIn( <target> , <val1> [, <val2>, ... [, <valN>] ] )
Example
IsIn( tFRUIT , "APPLE" , "PEAR" , "ORANGE" )
tFRUIT = "PEAR"
Returns True.
tFRUIT = "MANGO" Returns False.