Scala - Core Scala - More Collections(Option, Some, None, util.Try)

Learning Scala:
Practical Functional Programming for the JVM
(O'Reilly Media)
Jason Swartz (著)

開発環境

• OS X El Capitan - Apple (OS)
• Emacs (Text Editor)
• Scala (プログラミング言語)

Learning Scala: Practical Functional Programming for the JVM (Jason Swartz (著)、O'Reilly Media)のPart Ⅰ. (Core Scala)、Chapter 7.(More Collections)、Exercises 4.(No. 3195)を解いてみる。

その他参考書籍

• Programming Scala: Scalability = Functional Programming + Objects

Exercises 4.(No. 3195)

コード(Emacs)

def product(x: String, y: String):Option[Double] = {
  (util.Try(x.toDouble).toOption, util.Try(y.toDouble).toOption) match {
    case (Some(n), Some(m)) => Some(n * m)
    case _ => None
  }
}

println(product("5", "10"))
println(product("1.2", "10"))
println(product("5", "ten"))

入出力結果(Terminal, REPL(Read, Eval, Print, Loop))

$ scala-2.11 sample4.scala
Some(50.0)
Some(12.0)
None
$