Issue #5574 has been updated by Ondrej Bilka. I remember that in ruby-core long ago matz explained that array don't include comparable because they could contain elements that are not comparable. I dont see this as problem as this is violated in most classes when comparing field that can be nil. ---------------------------------------- Feature #5574: Make arrays comparable http://redmine.ruby-lang.org/issues/5574 Author: Arnau Sanchez Status: Open Priority: Normal Assignee: Category: Target version: Why are arrays not comparable? _Array_ already defines _<=>_, so it seems only natural to mix-in the _Comparable_ module. <pre> > [1, 2] < [1, 1] NoMethodError: undefined method `<' for [1, 2]:Array > Array.send(:include, Comparable) > [1, 2] < [1, 1] => false </pre> This was already discussed in the mailing list a while ago and people agreed it would be useful: http://www.ruby-forum.com/topic/76535 -- http://redmine.ruby-lang.org