-- Reads SP 500 stock data in the format provided by:
-- http://biz.swcp.com/stocks/
-- and creates time series for each stock.

-- There is one line per stock per day.  The fields are:
-- Date Ticker Open High Low Close Volume
-- They are separated by commas, but use a text editor to
-- replace commas by spaces before using this program.

-- The stocks are sorted by Ticker, and within a stock
-- by Date.  This program uses this fact in processing.

-- by Scot Drysdale on 10/14/07

module CovertStocks where

import qualified Data.Map as M

main = do
  contents <- readFile "spmohstSP.txt"
  let lineList = lines contents
  let wordsList = map words lineList
  let pairsList = map (extractDataPair 5) wordsList
  
  -- This call creates a map with stocks as keys.  Note that
  -- because foldr associates right the order ends up by date.
  let stockMap = foldr (insertWithPair (++)) M.empty pairsList
  writeFile "stockData.txt" (show (M.toList stockMap))
  
  
-- Creates a list of ticker name and another quantity (column
-- selected as described above).
extractDataPair       :: Int -> [String] -> (String, [Float])
extractDataPair pos ln = (ln !! 1, [read (ln !! pos)])

-- Allows input of a (k,v) pair instead of k v.
insertWithPair f (k, v) = M.insertWith f k v