gistfile1.rb

    # Delete duplicates
    rows = []
    res.each do |row|
      # skip if already saved in new array
      next if rows.detect { |r| r[3] == row[3] }
    
      # Find multiple instances sale
      rows_with_same_sale_id = res.select { |r| r[3] == row[3] }
    
      # create an array with only the markers ie. ["I", "N", "E"]
      same_sale_id_markers = rows_with_same_sale_id.map(&:first) 
      
      # Add I or N using I < N
      if same_sale_id_markers.include?("I") && !same_sale_id_markers.include?("N")
        rows << rows_with_same_sale_id.detect { |r| r.first == "I" }
      elsif same_sale_id_markers.include?("N")
        rows << rows_with_same_sale_id.detect { |r| r.first == "N" }
      end
      
      # Add E, D or C using E < (D,C)
      if same_sale_id_markers.include?("E") && (!same_sale_id_markers.include?("D") || !same_sale_id_markers.include?("C"))
        rows << rows_with_same_sale_id.detect { |r| r.first == "E" }
      elsif same_sale_id_markers.include?("D") || same_sale_id_markers.include?("C")
        rows << rows_with_same_sale_id.detect { |r| r.first == "D" } if same_sale_id_markers.include?("D")
        rows << rows_with_same_sale_id.detect { |r| r.first == "C" } if same_sale_id_markers.include?("C")
      end
      
    end