Gets a list of files in a given directory and all child directories

listFiles.scala

  /**
   * Gets a list of files in a given directory and all child directories
   * @param f This is the File representing the root directory
   * @return A list of File objects, each one representing a File inside f, either directly or in a sub-directory
   */
  def listFiles(f: File): List[File] = f match{
    case f if f.isDirectory => f.listFiles.toList.flatMap(listFiles(_))
    case f if f.isFile => List(f)
    case _ => Nil
  }