# File lib/table_print/row_group.rb, line 49
    def column_for(name)
      return parent.column_for(name) if parent
      column = @columns[name.to_s] ||= Column.new(:name => name)

      # assign the data sets to the column before we return it
      # do this as late as possible, since new rows could be added at any time
      column.data ||= raw_column_data(column.name)
      column
    end