I have a list of two values. The first is a slash (/) followed by a a number from 1 to 100, the second is o or 1 (e.g. "/14 0). I want to keep that list intact, but pick only those lists, where the second value is 1 (filter the ones where it is 0). I tried zl objects, but their complexity was overwhelming for a starter like me. Could somebody kindly gimme some advice?