第11章：Scalaの「Traversable」リファレンス ref: http://qiita.com/f81@github/items/62ad3c56ce6be271ef35

file0.scala

scala> Seq(1, 2, 3).foreach(print(_))
123

file1.scala

scala> Seq(1, 2, 3) ++ Seq(4, 5)
res1: Seq[Int] = List(1, 2, 3, 4, 5)

file10.scala

scala> Seq(1, 2, 3, 1) toSet
res10: scala.collection.immutable.Set[Int] = Set(1, 2, 3)

file11.scala

scala> Seq(1, 2, 3, 1) toStream
res11: scala.collection.immutable.Stream[Int] = Stream(1, ?)

file12.scala

scala>     var array = Array(4, 5, 6, 7, 8)
array: Array[Int] = Array(4, 5, 6, 7, 8)

scala>     Seq(1, 2, 3) copyToArray (array)

scala>     array
res12: Array[Int] = Array(1, 2, 3, 7, 8)

file13.scala

scala>     var buffer = scala.collection.mutable.Buffer(4, 5, 6, 7, 8)
buffer: scala.collection.mutable.Buffer[Int] = ArrayBuffer(4, 5, 6, 7, 8)

scala>     Seq(1, 2, 3) copyToBuffer (buffer)

scala>     buffer
res13: scala.collection.mutable.Buffer[Int] = ArrayBuffer(4, 5, 6, 7, 8, 1, 2, 3)

file14.scala

scala> Seq(1, 2, 3) isEmpty
res14: Boolean = false

scala> Seq() isEmpty
res15: Boolean = true

file15.scala

scala> Seq(1, 2, 3) nonEmpty
res16: Boolean = true

scala> Seq() nonEmpty
res17: Boolean = false

file16.scala

scala> Seq(1, 2, 3) size
res18: Int = 3

file17.scala

scala> Seq(1, 2, 3) find (_ > 1)
res19: Option[Int] = Some(2)

file18.scala

scala> Seq(1, 2, 3) head
res20: Int = 1

file19.scala

scala> Seq(1, 2, 3) headOption
res21: Option[Int] = Some(1)

file2.scala

scala> Seq("a", "b", "c") map (_.toUpperCase())
res2: Seq[java.lang.String] = List(A, B, C)

file20.scala

scala> Seq(1, 2, 3) last
res22: Int = 3

file21.scala

scala> Seq(1, 2, 3) lastOption
res23: Option[Int] = Some(3)

file22.scala

scala> Seq(1, 2, 3) init
res24: Seq[Int] = List(1, 2)

file23.scala

scala> Seq(1, 2, 3, 4, 5) take(2)
res25: Seq[Int] = List(1, 2)

file24.scala

scala> Seq(1, 2, 3) drop(2)
res26: Seq[Int] = List(3)

file25.scala

scala> Seq(1, 2, 3) filter (_ % 2 == 1)
res27: Seq[Int] = List(1, 3)

file26.scala

scala> Seq(1, 2, 3) filterNot(_ % 2 == 1)
res28: Seq[Int] = List(2)

file27.scala

scala> Seq(1, 2, 3, 4, 5) slice(2, 4)
res29: Seq[Int] = List(3, 4)

file28.scala

scala> Seq(1, 2, 3, 4, 5) tail
res30: Seq[Int] = List(2, 3, 4, 5)

file29.scala

scala> Seq(1, 2, 3, 4, 5) count (_ % 2 == 0)
res31: Int = 2

file3.scala

scala> Seq("red", "blue", "yellow") flatMap (_.toList)
res3: Seq[Char] = List(r, e, d, b, l, u, e, y, e, l, l, o, w)

file30.scala

scala> Seq(1, 2, 3, 4, 5) exists (_ > 4)
res32: Boolean = true

scala> Seq(1, 2, 3, 4, 5) exists (_ > 5)
res33: Boolean = false

file31.scala

scala> Seq(1, 2, 3, 4, 5) groupBy(_ > 3)
res34: scala.collection.immutable.Map[Boolean,Seq[Int]] = Map(false -> List(1, 2, 3), true -> List(4, 5))

file32.scala

scala> Seq(1, 2, 3, 4, 5) partition(_ > 3)
res35: (Seq[Int], Seq[Int]) = (List(4, 5),List(1, 2, 3))

file33.scala

scala> Seq(1, 2, 3, 4, 5) span(_ % 2 == 1)
res36: (Seq[Int], Seq[Int]) = (List(1),List(2, 3, 4, 5))

file34.scala

scala> Seq(1, 2, 3, 4, 5) splitAt (3)
res37: (Seq[Int], Seq[Int]) = (List(1, 2, 3),List(4, 5))

file35.scala

scala> Seq(1, 2, 3).foldLeft(10)(_ - _)
res38: Int = 4

file36.scala

scala> Seq(1, 2, 3).foldRight(10)(_ - _)
res39: Int = -8

file37.scala

scala> Seq(1, 2, 3).reduceLeft(_ - _)
res40: Int = -4

file38.scala

scala> Seq(1, 2, 3).reduceRight(_ - _)
res41: Int = 2

file39.scala

scala> Seq(1, 2, 3).sum
res42: Int = 6

file4.scala

scala> Seq(1, 2, 3) collect { case (i) if (i % 2 == 1) => i + 1 }
res4: Seq[Int] = List(2, 4)

file40.scala

scala> Seq(1, 2, 3).product
res43: Int = 6

file41.scala

scala> Seq(1, 2, 3) min
res44: Int = 1

file42.scala

scala> Seq(1, 2, 3) max
res45: Int = 3

file43.scala

scala> var builder = new StringBuilder
builder: StringBuilder =

scala> Seq(1, 2, 3) addString(builder)
res46: StringBuilder = 123

file44.scala

scala> Seq(1, 2, 3) mkString ("a")
res47: String = 1a2a3

file45.scala

scala> Seq(1, 2, 3) view
res48: java.lang.Object with scala.collection.SeqView[Int,Seq[Int]] = SeqView(..)

file5.scala

scala> Seq(1, 2, 3) toArray
res5: Array[Int] = Array(1, 2, 3)

file6.scala

scala> Seq(1, 2, 3) toIterable
res6: Iterable[Int] = List(1, 2, 3)

file7.scala

scala> Seq(1, 2, 3) toList
res7: List[Int] = List(1, 2, 3)

file8.scala

scala> Seq((1,"Moses"), (2,"Lucas"), (3,"Henderson")) toMap
res8: scala.collection.immutable.Map[Int,java.lang.String] = Map(1 -> Moses, 2 -
> Lucas, 3 -> Henderson)

file9.scala

scala> Map(1 -> "Moses", 2 -> "Lucas", 3 -> "Henderson").toSeq
res9: Seq[(Int, java.lang.String)] = ArrayBuffer((1,Moses), (2,Lucas), (3,Hender
son))