# File lib/ruport/data/table.rb, line 533
    def sub_table(cor=column_names,range=nil,&block)
      if range
        self.class.new(:column_names => cor,:data => data[range])
      elsif cor.kind_of?(Range)
        self.class.new(:column_names => column_names,:data => data[cor])
      elsif block
        self.class.new( :column_names => cor, :data => data.select(&block))
      else
        self.class.new( :column_names => cor, :data => data)  
      end 
    end