Scala: 正規表現でマッチするかどうか調べる方法

いろんな方法がある

"1234".matches("""\d{4}""")                       //> res0: Boolean = true

new scala.util.matching.Regex("""\d{4}""").findFirstIn("1234").nonEmpty
                                                  //> res1: Boolean = true

"""\d{4}""".r.findFirstIn("1234").nonEmpty        //> res2: Boolean = true


val dateP1 = """(\d\d\d\d)-(\d\d)-(\d\d)""".r     //> dateP1  : scala.util.matching.Regex = (\d\d\d\d)-(\d\d)-(\d\d)

"2011-07-15" match {
    case dateP1(year, month, day) => true
    case _ => false
}                                                 //> res3: Boolean = true


val dateP1(year, month, day) = "2011-07-15"       //> year  : String = 2011
                                                  //| month  : String = 07
                                                  //| day  : String = 15

dateP1.findAllIn("2011-07-15").matchData.foreach { m =>
    println(m.group(0))
    println(m.group(1))
    println(m.group(2))
    println(m.group(3))
}                                                 //> 2011-07-15
                                                  //| 2011
                                                  //| 07
                                                  //| 15

val dateP2 = new scala.util.matching.Regex("""(\d\d\d\d)-(\d\d)-(\d\d)""", "year", "month", "day")
                                                  //> dateP2  : scala.util.matching.Regex = (\d\d\d\d)-(\d\d)-(\d\d)

dateP2.findAllIn("2011-07-15").matchData.foreach { m =>
    println(m.group("year"))
    println(m.group("month"))
    println(m.group("day"))
}                                                 //> 2011
                                                  //| 07
                                                  //| 15