How do I list all files in a subdirectory in scala?

Question

Is there a good \"scala-esque\" (I guess I mean functional) way of recursively listing files in a directory? What about matching a particular pattern?

For example re

Answer 1

I personally like the elegancy and simplicity of @Rex Kerr's proposed solution. But here is what a tail recursive version might look like:

def listFiles(file: File): List[File] = {
  @tailrec
  def listFiles(files: List[File], result: List[File]): List[File] = files match {
    case Nil => result
    case head :: tail if head.isDirectory =>
      listFiles(Option(head.listFiles).map(_.toList ::: tail).getOrElse(tail), result)
    case head :: tail if head.isFile =>
      listFiles(tail, head :: result)
  }
  listFiles(List(file), Nil)
}