gistfile1.rb

  def draw_chart(collection, attribute=nil, &block)
    if attribute
      grouped = collection.group_by(&attribute)
    elsif block
      grouped = collection.group_by(&block)
    else
      raise "Must provide either an attribute or block to group by!"
    end

    # try to sort them, but if they're not sortable, don't worry about it
    begin
      grouped = grouped.sort_by(&:first)
    rescue ArgumentError
    end

    puts AsciiCharts::Cartesian.new(grouped.map { |k, v| [k, v.count] }).draw
    nil
  end