Split a filename into absolute paths in Scala

Question

Given the string

val path = "/what/an/awesome/path" 

how can I use Scala to create a list of absolute paths for each directory in path? The result should be:

List(/what, /what/an, /what/an/awesome, /what/an/awesome/path)

Bonus points for an elegant, functional solution.

Answer 1

val path = "/what/an/awesome/path"
val file = new java.io.File(path)
val prefixes = Iterator.iterate(file)(_.getParentFile).takeWhile(_ != null).toList.reverse

Answer 2

val path = "/what/an/awesome/path"

scala> path.tail.split("/").scanLeft(""){_ + "/" + _}.tail.toList
res1: List[java.lang.String] = List(/what, /what/an, /what/an/awesome, /what/an/awesome/path)

Answer 3

Using Jesse Eichar's new Scala IO library (version 0.2.0) it looks like you can do something like this:

val path  = Path("/what/an/awesome/path")
val paths = (path :: path.parents).reverse

You might want to convert the Path objects in the resulting list to Strings but perhaps they would be safer and more useful left as Path objects.

This library, as far as I know, is being considered for inclusion in the Scala distribution.

Answer 4

path.drop(1).split("/").foldLeft(List.empty[String])((list, string) => ((list.headOption.getOrElse("") + "/" + string) :: list)).reverse.toList

There's probably a cleaner way using scanLeft, but I wasn't able to figure it out