# File lib/ai4r/classifiers/hyperpipes.rb, line 105
      def update_pipe(pipe, data_item)
        data_item[0...-1].each_with_index do |att, i|
          if att.is_a? Numeric
            pipe[i][:min] = att if att < pipe[i][:min]
            pipe[i][:max] = att if att > pipe[i][:max]
          else
            pipe[i][att] = true
          end  
        end
      end