|      1 // Main Part 1 about a really dumb investment strategy |      1 // Main Part 1 about a really dumb investment strategy | 
|      2 //===================================================== |      2 //=================================================== | 
|      3  |      3  | 
|      4  |      4 object M1 { | 
|      5 // generate jar with |         | 
|      6 //   > scala -d drumb.jar  drumb.scala |         | 
|      7  |         | 
|      8  |         | 
|      9 object M1 {  |         | 
|     10  |         | 
|     11  |      5  | 
|     12 //two test portfolios |      6 //two test portfolios | 
|     13  |      7  | 
|     14 val blchip_portfolio = List("GOOG", "AAPL", "MSFT", "IBM", "FB", "AMZN", "BIDU") |      8 val blchip_portfolio = List("GOOG", "AAPL", "MSFT", "IBM", "FB", "AMZN", "BIDU") | 
|     15 val rstate_portfolio = List("PLD", "PSA", "AMT", "AIV", "AVB", "BXP", "CCI",  |      9 val rstate_portfolio = List("PLD", "PSA", "AMT", "AIV", "AVB", "BXP", "CCI",  | 
|     16                             "DLR", "EQIX", "EQR", "ESS", "EXR", "FRT", "HCP")  |     10                             "DLR", "EQIX", "EQR", "ESS", "EXR", "FRT", "HCP")  | 
|     17  |     11  | 
|     18 import io.Source |     12 import io.Source | 
|     19 import scala.util._ |     13 import scala.util._ | 
|     20  |     14  | 
|     21 // (1) The function below takes a stock symbol and a year as arguments. |     15 // ADD YOUR CODE BELOW | 
|     22 //     It should read the corresponding CSV-file and reads the January  |     16 //====================== | 
|     23 //     data from the given year. The data should be collected in a list of |         | 
|     24 //     strings for each line in the CSV-file. |         | 
|     25  |         | 
|     26 def get_january_data(symbol: String, year: Int) : List[String] =  |         | 
|     27   Source.fromFile(symbol ++ ".csv")("ISO-8859-1").getLines().toList.filter(_.startsWith(year.toString)) |         | 
|     28  |     17  | 
|     29  |     18  | 
|     30 //test cases |     19 // (1)  | 
|     31 //blchip_portfolio.map(get_january_data(_, 2018)) |     20 def get_january_data(symbol: String, year: Int) : List[String] = { | 
|     32 //rstate_portfolio.map(get_january_data(_, 2018)) |     21   Try(Source.fromFile(s"${symbol}.csv").getLines.toList.filter(_.startsWith(year.toString))).getOrElse(Nil) | 
|     33  |     22 } | 
|     34 //get_january_data("GOOG", 1980) |     23 // (2)  | 
|     35 //get_january_data("GOOG", 2010) |         | 
|     36 //get_january_data("FB", 2014) |         | 
|     37  |         | 
|     38 //get_january_data("PLD", 1980) |         | 
|     39 //get_january_data("EQIX", 2010) |         | 
|     40 //get_january_data("ESS", 2014) |         | 
|     41  |         | 
|     42  |         | 
|     43 // (2) From the output of the get_january_data function, the next function  |         | 
|     44 //     should extract the first line (if it exists) and the corresponding |         | 
|     45 //     first trading price in that year with type Option[Double]. If no line  |         | 
|     46 //     is generated by get_january_data then the result is None; Some if  |         | 
|     47 //     there is a price. |         | 
|     48  |         | 
|     49 def get_first_price(symbol: String, year: Int) : Option[Double] = { |     24 def get_first_price(symbol: String, year: Int) : Option[Double] = { | 
|     50   val data = Try(Some(get_january_data(symbol, year).head)) getOrElse None  |     25   val list = get_january_data(symbol, year) | 
|     51   data.map(_.split(",").toList(1).toDouble) |     26   if (list == Nil) None else { | 
|     52 } |     27     Some(list.head.split(",").toList(1).toDouble) | 
|     53  |         | 
|     54 //test cases |         | 
|     55 //get_first_price("GOOG", 1980) |         | 
|     56 //get_first_price("GOOG", 2010) |         | 
|     57 //get_first_price("FB", 2014) |         | 
|     58  |         | 
|     59 /* |         | 
|     60 for (i <- 1978 to 2018) { |         | 
|     61   println(blchip_portfolio.map(get_first_price(_, i))) |         | 
|     62 } |         | 
|     63  |         | 
|     64 for (i <- 1978 to 2018) { |         | 
|     65   println(rstate_portfolio.map(get_first_price(_, i))) |         | 
|     66 } |         | 
|     67 */  |         | 
|     68  |         | 
|     69  |         | 
|     70 // (3) Complete the function below that obtains all first prices |         | 
|     71 //     for the stock symbols from a portfolio (list of strings) and  |         | 
|     72 //     for the given range of years. The inner lists are for the |         | 
|     73 //     stock symbols and the outer list for the years. |         | 
|     74  |         | 
|     75 def get_prices(portfolio: List[String], years: Range): List[List[Option[Double]]] =  |         | 
|     76   for (year <- years.toList) yield |         | 
|     77     for (symbol <- portfolio) yield get_first_price(symbol, year) |         | 
|     78  |         | 
|     79  |         | 
|     80 //test cases |         | 
|     81  |         | 
|     82 //println("Task 3 data from Google and Apple in 2010 to 2012") |         | 
|     83 //val goog_aapl_prices = get_prices(List("GOOG", "AAPL"), 2010 to 2012) |         | 
|     84 //println(goog_aapl_prices.toString ++ "\n") |         | 
|     85  |         | 
|     86 //val p_fb = get_prices(List("FB"), 2012 to 2014) |         | 
|     87 //val tt = get_prices(List("BIDU"), 2004 to 2008) |         | 
|     88  |         | 
|     89  |         | 
|     90 // (4) The function below calculates the change factor (delta) between |         | 
|     91 //     a price in year n and a price in year n + 1.  |         | 
|     92  |         | 
|     93 def get_delta(price_old: Option[Double], price_new: Option[Double]) : Option[Double] = { |         | 
|     94   (price_old, price_new) match { |         | 
|     95     case (Some(x), Some(y)) => Some((y - x) / x) |         | 
|     96     case _ => None |         | 
|     97   } |     28   } | 
|     98 } |     29 } | 
|     99  |     30  | 
|    100  |     31  | 
|    101 // (5) The next function calculates all change factors for all prices (from a  |     32 // (3)  | 
|    102 //     portfolio). The input to this function are the nested lists created by  |     33 def get_prices(portfolio: List[String], years: Range) : List[List[Option[Double]]] = { | 
|    103 //     get_prices above. |     34   for (n <- years.toList) yield{ | 
|    104  |     35     for (m <- portfolio) yield{ | 
|    105 def get_deltas(data: List[List[Option[Double]]]):  List[List[Option[Double]]] = |     36       get_first_price(m, n) | 
|    106   for (i <- (0 until (data.length - 1)).toList) yield  |     37     } | 
|    107     for (j <- (0 until (data(0).length)).toList) yield get_delta(data(i)(j), data(i + 1)(j)) |         | 
|    108  |         | 
|    109  |         | 
|    110  |         | 
|    111 // test case using the prices calculated above |         | 
|    112  |         | 
|    113 //println("Task 5 change prices from Google and Apple in 2010 and 2011") |         | 
|    114 //val goog_aapl_deltas = get_deltas(goog_aapl_prices) |         | 
|    115 //println(goog_aapl_deltas.toString ++ "\n") |         | 
|    116  |         | 
|    117 //val ttd = get_deltas(tt) |         | 
|    118  |         | 
|    119  |         | 
|    120 // (6) Write a function that given change factors, a starting balance and an index, |         | 
|    121 //     calculates the yearly yield, i.e. new balance, according to our dumb investment  |         | 
|    122 //     strategy. Index points to a year in the data list. |         | 
|    123  |         | 
|    124 def yearly_yield(data: List[List[Option[Double]]], balance: Long, index: Int): Long = { |         | 
|    125   val somes = data(index).flatten |         | 
|    126   val somes_length = somes.length |         | 
|    127   if (somes_length == 0) balance |         | 
|    128   else { |         | 
|    129     val portion: Double = balance.toDouble / somes_length.toDouble |         | 
|    130     balance + (for (x <- somes) yield (x * portion)).sum.toLong |         | 
|    131   } |     38   } | 
|    132 } |         | 
|    133  |         | 
|    134 // test case using the deltas calculated above |         | 
|    135 //println("Task 6 yield from Google and Apple in 2010 with  balance 100") |         | 
|    136  |         | 
|    137 //val d0 = goog_aapl_deltas(0)(0) |         | 
|    138 //val d1 = goog_aapl_deltas(0)(1) |         | 
|    139 //println(s"50 * ${d0.get} + 50 * ${d1.get} = ${50.toDouble * d0.get + 50.toDouble * d1.get}") |         | 
|    140  |         | 
|    141  |         | 
|    142 //val goog_aapl_yield = yearly_yield(goog_aapl_deltas, 100, 0) |         | 
|    143 //println("Rounded yield: " ++ goog_aapl_yield.toString ++ "\n") |         | 
|    144  |         | 
|    145  |         | 
|    146 //yearly_yield(get_prices(rstate_portfolio, 2016 to 2018), 100, 2)  |         | 
|    147 //get_prices(rstate_portfolio, 2016 to 2018)(2).flatten.sum |         | 
|    148  |         | 
|    149  |         | 
|    150 // (7) Write a function compound_yield that calculates the overall balance for a  |         | 
|    151 //     range of years where in each year the yearly profit is compounded to the new  |         | 
|    152 //     balances and then re-invested into our portfolio. For this use the function and  |         | 
|    153 //     results generated under (6). The function investment calls compound_yield |         | 
|    154 //     with the appropriate deltas and the first index. |         | 
|    155  |         | 
|    156  |         | 
|    157 def compound_yield(data: List[List[Option[Double]]], balance: Long, index: Int): Long = { |         | 
|    158   if (index >= data.length) balance else { |         | 
|    159     val new_balance = yearly_yield(data, balance, index) |         | 
|    160     compound_yield(data, new_balance, index + 1) |         | 
|    161   } |         | 
|    162 } |         | 
|    163  |         | 
|    164 def investment(portfolio: List[String], years: Range, start_balance: Long): Long = { |         | 
|    165   compound_yield(get_deltas(get_prices(portfolio, years)), start_balance, 0) |         | 
|    166 } |     39 } | 
|    167  |     40  | 
|    168  |     41  | 
|    169  |     42  | 
|    170 //test cases for the two portfolios given above |     43 // (4)  | 
|         |     44 def get_delta(price_old: Option[Double], price_new: Option[Double]) : Option[Double] = { | 
|         |     45   if (price_old != None && price_new != None) Some((price_new.get - price_old.get) / price_old.get) else None | 
|         |     46 } | 
|    171  |     47  | 
|    172   println("Real data: " + investment(rstate_portfolio, 1978 to 2019, 100)) |     48  | 
|    173   println("Blue data: " + investment(blchip_portfolio, 1978 to 2019, 100)) |     49  | 
|         |     50 // (5)  | 
|         |     51 def get_deltas(data: List[List[Option[Double]]]) :  List[List[Option[Double]]] = { | 
|         |     52   for (n <- data.tail) yield{ | 
|         |     53     for (m <- n) yield{ | 
|         |     54       get_delta(data(data.tail.indexOf(n))(n.indexOf(m)),m) | 
|         |     55     } | 
|         |     56   } | 
|         |     57 } | 
|         |     58  | 
|         |     59 // (6)  | 
|         |     60 def yearly_yield(data: List[List[Option[Double]]], balance: Long, index: Int) : Long = { | 
|         |     61   if(data.length == 0) balance else{ | 
|         |     62     val equal = balance / data(index).flatten.length | 
|         |     63     val list = for(n <- data(index).flatten) yield n * equal | 
|         |     64     (balance + list.sum).toLong | 
|         |     65   } | 
|         |     66 } | 
|         |     67  | 
|         |     68 // (7)  | 
|         |     69 def compound_yield(data: List[List[Option[Double]]], balance: Long, index: Int) : Long = { | 
|         |     70   val deltas = get_deltas(data) | 
|         |     71   if (deltas.length == 0) balance else{ | 
|         |     72       if(deltas.length - 1 == index) yearly_yield(deltas, balance, index) else compound_yield(data, yearly_yield(deltas, balance, index), index + 1) | 
|         |     73   } | 
|         |     74 } | 
|         |     75  | 
|         |     76 def investment(portfolio: List[String], years: Range, start_balance: Long) : Long = { | 
|         |     77   val list = get_prices(portfolio, years) | 
|         |     78   compound_yield(list, start_balance, 0) | 
|         |     79 } | 
|         |     80  | 
|         |     81  | 
|         |     82  | 
|         |     83  | 
|         |     84 //Test cases for the two portfolios given above | 
|         |     85  | 
|         |     86 //println("Real data: " + investment(rstate_portfolio, 1978 to 2019, 100)) | 
|         |     87 //println("Blue data: " + investment(blchip_portfolio, 1978 to 2019, 100)) | 
|    174  |     88  | 
|    175  |     89  | 
|    176 } |     90 } | 
|    177  |     91  | 
|    178  |     92  | 
|    179  |     93  | 
|    180  |     94  | 
|    181  |     95 // This template code is subject to copyright  | 
|    182  |     96 // by King's College London, 2022. Do not  | 
|    183  |     97 // make the template code public in any shape  | 
|    184  |     98 // or form, and do not exchange it with other  | 
|    185  |     99 // students under any circumstance. | 
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