Nub Sieve: Difference between revisions

{{Primitive|≠|Nub Sieve}}, '''Nubsieve''', or '''Unique Mask''', is a [[monadic function]] that returns a [[Boolean]] [[vector]] indicating which [[major cells]] of its argument would be included in the result of [[Unique]] (Nub). More precisely, it indicates all cells which do not [[match]] any earlier indicated cell. The Nub Sieve is more informative than Unique because it encodes not only which cells are unique but where they appear in the argument. This means it can be used for tasks such as filtering secondary arrays and working with duplicates that are difficult to do with Unique and slow to compute with [[Key]].