Use the
filterlist() function, as defined in the Help under StreamBase Home > StreamBase References > StreamBase Expression Language Functions > (sub-heading) Simple Functions: Lists. For example, if the tuple list element has a Named Schema 'Customer' with sub-fields 'name' and 'status', you can filter out inactive entries in a Map operator using the following expression:
filterlist(input1.Customer, function notInactive(cust Customer) {cust.status != 'inactive'})
This expression creates a user-defined function, 'notInactive', which applies the predicate
cust.status != 'inactive'.