progs/trade_sol.scala
changeset 127 b4def82f3f9f
parent 126 c40f364d87eb
child 128 166bb9b6b20a
--- a/progs/trade_sol.scala	Sun Nov 05 12:56:55 2017 +0000
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,79 +0,0 @@
-// Part 2 about Buy-Low-Sell-High using Yahoo Financial Data
-//===========================================================
-
-
-// (1) Complete the function that is given a list of floats
-// and calculuates the indices for when to buy the commodity 
-// and when to sell
-
-def trade_times(xs: List[Double]): (Int, Int) = {
-  val low = xs.min
-  val low_index = xs.indexOf(low)
-  val rest = xs.drop(low_index)
-  val high = rest.max
-  val high_index = rest.indexOf(high)
-  (low_index, low_index + high_index)
-}
-
-val prices = List(28.0, 18.0, 20.0, 26.0, 24.0)
-assert(trade_times(prices) == (1, 3), "the trade_times test fails")
-
-
-// (2) Complete the ``get webpage'' function that takes a
-// a stock symbol as argument and queries the Yahoo server
-// at
-//      http://ichart.yahoo.com/table.csv?s=<<insert stock symbol>>
-// 
-// This servive returns a CSV-list that needs to be separated into
-// a list of strings.
-
-import io.Source
-import scala.util._
-
-def get_yahoo_page(symbol: String): List[String] = {
-  val url = """http://ichart.yahoo.com/table.csv?s=""" + symbol
-  Try(Source.fromURL(url)("ISO-8859-1").getLines.toList).
-    getOrElse { println(s"  Problem with: $url"); List() }
-}
-
-// (3) Complete the function that processes the CSV list
-// extracting the dates and anjusted close prices. The
-// prices need to be transformed into Doubles.
-
-def process_page(symbol: String): List[(String, Double)] = {
-  get_yahoo_page(symbol).drop(1).map(_.split(",").toList).map((xs) => (xs(0), xs(6).toDouble))
-}
-
-
-// (4) Complete the query_company function that obtains the
-// processed CSV-list for a stock symbol. It should return
-// the dates for when to buy and sell the stocks of that company.
-
-def query_company(symbol: String): (String, String) = {
-  val list = process_page(symbol).reverse
-  val (tbuy, tsell) = trade_times(list.map(_._2))
-  (list(tbuy)._1, list(tsell)._1)
-}
-
-//query_company("GOOG")
-
-
-val indices = List("GOOG", "AAPL", "MSFT", "IBM", "FB", "YHOO", "AMZN", "BIDU")
-
-for (name <- indices) {
-  val times = query_company(name)
-  println(s"Buy ${name} on ${times._1} and sell on ${times._2}")
-}
-
-
-
-/*
-scala trade.scala 2> /dev/null || echo "command1 borked it"
-
-command1
-if [ $? -ne 0 ]; then
-    echo "command1 borked it"
-fi
-*/
-
-