gistfile1.scala

/**
 * Given a sequence of words (Array, List, etc), generate a Map[String, Int]
 * of the words to how many times they appear in the sequence, filtering any
 * stop words.
 */
def countWords(w: Seq[String], s: Seq[String]) =
  w.filter(! s.contains(_)).foldLeft(Map[String, Int]()) { (m, w) =>
    m + {
      if(m.isDefinedAt(w)) w -> (m(w) + 1)
      else w -> 1
    }
  }
 
 
val words = "web designer to the max web me sideways i love web i am a designer".split(" ")
val stopWords = "and the to a it is i am me".split(" ")
val totals = countWords(words, stopWords)
//totals: scala.collection.immutable.Map[String,Int] = Map(web -> 3, sideways -> 1, love -> 1, max -> 1, designer -> 2)

// If you want to sort them by appearance frequency:
val frequencyList = totals.toList.sort(_._2 > _._2)

// If you want to create a string of the 3 most popular terms:
frequencyList.take(3).foldLeft("")(_ + " " + _._1)
//res0: java.lang.String =  web designer max