Collections exos

base_tp/src/collection/collect.scala

+package ch.hepia.tpscala
+
+
+/* Implémentez les fonctions suivantes. 
+ */
+object Collect {
+
+  case class Album( title: String, artist: String, year: Int )
+  case class Duration( minutes: Int, seconds: Int )
+  case class Track( title: String, duration: Duration )
+
+  val albums = List(
+    Album( "Mit Gas", "Tomahawk", 2003 ),
+    Album( "Pork Soda", "Primus", 1993 ),
+    Album( "Brown Album", "Primus", 1997 ),
+    Album( "Distraction Pieces", "Scroobius Pip", 2011 )
+  )
+
+  val tracks = Map(
+    "Mit Gas" -> List(
+      Track( "Mayday", Duration( 3, 32 ) )
+    ),
+    "Pork Soda" -> List(
+      Track( "DMV", Duration( 4, 58 ) ),
+      Track( "Mr. Krinkle", Duration( 5, 27 ) )
+    ),
+    "Brown Album" -> List(
+      Track( "Fisticuffs", Duration( 4, 25 ) ),
+      Track( "Camelback Cinema", Duration( 4, 0 ) ),
+      Track( "Kalamazoo", Duration( 3, 31 ) )
+    ),
+    "Distraction Pieces" -> List(
+      Track( "Let 'Em Come", Duration( 4, 25 ) ),
+      Track( "Domestic Silence", Duration( 3, 58 ) )
+    )
+  )
+
+  /* Retourne la liste de morceaux associés à un artiste */
+  def tracksOf( artist: String ): List[Track] = {
+    albums.filter(_.artist == artist).flatMap( a => tracks(a.title))
+  }
+
+  /* Retourne la liste de tous les morceaux de moins de 4 minutes */
+  def shortTracks: List[Track] = {
+    tracks.flatMap(t => t._2).filter(t => t.duration.minutes < 4).toList
+  }
+
+  /* Retourne les titres des morceaux antérieurs à une année */
+  def titlesBefore( year: Int ): List[String] = {
+    albums.flatMap(a => if (a.year < year) tracks(a.title) else List()).map(_.title)
+  }
+
+  /* Calcule la durée totale de tous les morceaux disponibles.
+     REMARQUE: on veut que les secondes soient inférieures à 60 mais les
+     minutes peuvent dépasser ce total.
+   */
+  def totalDuration: Duration = {
+    var m = 0
+    var s = 0
+    tracks.flatMap(_._2).foreach(t => {
+      m += t.duration.minutes
+      s += t.duration.seconds
+    })
+    Duration(m + s/60, s % 60)
+  }
+}

base_tp/test/collectTest.scala

+package ch.hepia.tpscala
+
+import org.scalatest.funsuite.AnyFunSuite
+
+import Collect._
+
+class Collect6Suite extends AnyFunSuite {
+
+  test( "tracksOf" ) {
+    assert( tracksOf("Justin Bieber").isEmpty )
+    assert( tracksOf("Tomahawk") == List( Track( "Mayday", Duration( 3, 32 ) ) ) )
+    assert( tracksOf("Primus").size == 5 )
+  }
+
+  test( "shortTracks" ) {
+    assert(
+      shortTracks.toSet == Set(
+        Track( "Mayday", Duration( 3, 32 ) ),
+        Track( "Kalamazoo", Duration( 3, 31 ) ),
+        Track( "Domestic Silence", Duration( 3, 58 ) )
+      )
+    )
+  }
+
+  test( "titlesBefore" ) {
+    assert( titlesBefore( 1928 ).size == 0 )
+    assert( titlesBefore( 2020 ).size == 8 )
+    assert(
+      titlesBefore( 2000 ).toSet == Set(
+        "DMV",
+        "Mr. Krinkle",
+        "Fisticuffs",
+        "Camelback Cinema",
+        "Kalamazoo"
+      )
+    )
+  }
+
+  test( "totalDuration" ) {
+    assert( totalDuration == Duration( 34, 16 ) )
+  }
+
+
+
+}