1 

     2 import CW7b._

     3 

     4 // first test 

     5 

     6 def urban_groupById(ratings: List[(String, String)], 

     7               m: Map[String, List[String]]) : Map[String, List[String]] = ratings match {

     8   case Nil => m

     9   case (id, mov) :: rest => {

    10     val old_ratings = m.getOrElse (id, Nil)

    11     val new_ratings = m + (id -> (mov :: old_ratings))

    12     urban_groupById(rest, new_ratings)

    13   }

    14 }

    15 //def urban_groupById(ratings: List[(String, String)]) = 

    16 //  ratings.groupBy(_._1).view.mapValues(_.map(_._2)).toMap 

    17 

    18 def urban_get_csv_file(name: String) : List[String] = {

    19   import io.Source

    20   import scala.util._

    21   val csv = Source.fromFile(name)("ISO-8859-1")

    22   csv.mkString.split("\n").toList.drop(1)

    23 }

    24 

    25 def urban_process_ratings(lines: List[String]) : List[(String, String)] = {

    26   for (cols <- lines.map(_.split(",").toList); 

    27        if (cols(2).toInt >= 4)) yield (cols(0), cols(1))  

    28 }

    29 

    30 def urban_process_movies(lines: List[String]) : List[(String, String)] = {

    31   for (cols <- lines.map(_.split(",").toList)) yield (cols(0), cols(1))  

    32 }

    33 

    34 

    35 val urban_good_ratings = urban_process_ratings(urban_get_csv_file("ratings.csv"))

    36 val urban_movie_names = urban_process_movies(urban_get_csv_file("movies.csv"))

    37 

    38 val urban_movie_names_map = urban_movie_names.toMap

    39 val urban_ratings_map = urban_groupById(urban_good_ratings, Map())

    40 //val urban_ratings_map = groupById(urban_good_ratings, Map())

    41 

    42 val urban_ratings_map2 =  for ((k, v) <- urban_ratings_map) yield (k, v.take(2))

    43 

    44 assert(most_recommended(urban_ratings_map2, urban_movie_names_map).take(3) == 

    45        List(("M*A*S*H (a.k.a. MASH) (1970)",15), 

    46             ("Star Trek: First Contact (1996)",10), 

    47             ("Inception (2010)",9)))

    48