parser.rb

require 'fastercsv'
class StockParser::Parser
  attr_reader :rows

  def initialize
    @rows=[]
  end

  def import(data)
    @rows = FasterCSV.parse(data, :headers => true)
  end

  def companies
    @rows.map{|row| row['stock_symbol']}.uniq
  end

  def start_date
    @rows.map{|row| Date.parse row['date']}.min
  end

  def end_date
    @rows.map{|row| Date.parse row['date']}.max
  end

  # { "KBG" => {"max_open" => 22.0, "min_open" => 23.0}}
  def price_data
    @price_date ||= @rows.inject({}) do |hash, row|
      company = row['stock_symbol']
      price = row['stock_price_open'].to_f
      
      hash[company] = {"max_open" => price, "min_open" => price} unless hash.has_key?(company)
      hash[company]['max_open'] = price if price > hash[company]['max_open']
      hash[company]['min_open'] = price if price < hash[company]['min_open']
      hash
    end
  end
end