[ferret_users] existence of elements in array

[Marco van Hulten <Marco.Hulten@xxxxxx>]

Hello,
 
I would like to see if certain elements are in an array.  Suppose I
have and array  aa = {1, 2, 3} ,  I want to check if a number is in the
array (pseudo-ferret code):
 
if `3 \in aa` then say "3 is in aa"
if `7 \in aa` then say "7 is in aa"
 
How would you write out the \in in Ferret?
 
Or, using fewer characters, a case statement like (pseudo-bash code):
 
case bb in
3) say "3 is in aa"
7) say "7 is in aa"
 
Is there any equivalent in classical Ferret?
 
In the end I want to do this with an array of strings.
 
- Marco