function takes a string and returns a map of characters to frequency

charfreq.scala

def charFrequency(str: String): Map[Char, Int] = {
  var chars = Map[Char, Int]()
  for {
    c <- str
    if c != ' '
  } {
    chars += (c.toLower -> (chars.getOrElse(c, 0) + 1))
  }
  chars
}