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 like yura's stream solution, but it (and the others) recurses into hidden directories. We can also simplify by making use of the fact that listFiles returns null for a non-directory.

def tree(root: File, skipHidden: Boolean = false): Stream[File] = 
  if (!root.exists || (skipHidden && root.isHidden)) Stream.empty 
  else root #:: (
    root.listFiles match {
      case null => Stream.empty
      case files => files.toStream.flatMap(tree(_, skipHidden))
  })

Now we can list files

tree(new File(".")).filter(f => f.isFile && f.getName.endsWith(".html")).foreach(println)

or realise the whole stream for later processing

tree(new File("dir"), true).toArray