Splitting string into groups

Question

I\'m trying to \'group\' a string into segments, I guess this example would explain it more succintly

scala> val str: String = \"aaaabbcddeeeeeeffg\"
...          


        

Answer 1

def group(s: String): List[String] = s match {
  case "" => Nil
  case s  => s.takeWhile(_==s.head) :: group(s.dropWhile(_==s.head))
}

---

Edit: Tail recursive version:

def group(s: String, result: List[String] = Nil): List[String] = s match {
  case "" => result reverse
  case s  => group(s.dropWhile(_==s.head), s.takeWhile(_==s.head) :: result)
}

can be used just like the other because the second parameter has a default value and thus doesnt have to be supplied.