Scala：字符串模式匹配

Question

The below code takes the first two character of string and check if pattern is "de" or None it returns None else it returns the Test("Found")

val s =Option("abc")
val t = s.map(_.take(2))
case class Test(id:String)

t match {
  case Some("de") => None
  case None => None
  case _ => Test("Found")
}

Can anyone suggest a efficient solution for case matching

Answer 1

I think I get what you're asking so let me try this:

val condition = Option("abc").exists(_.toLower.take(2) == "de")
val output: Any = if(condition) Test("found") else None

The first portion returns false if the Option is None . It also returns false if the first two letters of the string are "de" in a case insensitive way.

The second portion returns either a None or a Test object. However, I want to point out that this results in an Any . Did you mean for it to return a Option[Test] type instead?

Answer 2

I assume, you meant Some(Test("Found")) in the last line of your snippet, judging from your comment to the other answer. If so, this is what you are looking for:

t.filterNot(_.take(2) == "de").map(_ => Test("Found"))