# File lib/ruport/data/table.rb, line 525
    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