# File lib/ai4r/data/data_set.rb, line 196 def << data_item if data_item.nil? || !data_item.is_a?(Enumerable) || data_item.empty? raise ArgumentError, "Data must not be an non empty array." elsif @data_items.empty? set_data_items([data_item]) elsif data_item.length != num_attributes raise ArgumentError, "Number of attributes do not match. " + "#{data_item.length} attributes provided, " + "#{num_attributes} attributes expected." else @data_items << data_item end end