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

Here's a similar solution to Rex Kerr's, but incorporating a file filter:

import java.io.File
def findFiles(fileFilter: (File) => Boolean = (f) => true)(f: File): List[File] = {
  val ss = f.list()
  val list = if (ss == null) {
    Nil
  } else {
    ss.toList.sorted
  }
  val visible = list.filter(_.charAt(0) != '.')
  val these = visible.map(new File(f, _))
  these.filter(fileFilter) ++ these.filter(_.isDirectory).flatMap(findFiles(fileFilter))
}

The method returns a List[File], which is slightly more convenient than Array[File]. It also ignores all directories that are hidden (ie. beginning with '.').

It's partially applied using a file filter of your choosing, for example:

val srcDir = new File( ... )
val htmlFiles = findFiles( _.getName endsWith ".html" )( srcDir )