I develop an application that builds pairs of words in (tokenised) text and produces the number of times each pair occurs (even when same-word pairs occur multiple times, it's OK as it'll be evened out later in the algorithm).

When I use

elements groupBy()

I want to group by the elements' content itself, so I wrote the following:

def self(x: (String, String)) = x

/**
 * Maps a collection of words to a map where key is a pair of words and the 
 *  value is number of
 * times this pair
 * occurs in the passed array
 */
def producePairs(words: Array[String]): Map[(String,String), Double] = {
  var table = List[(String, String)]()
  words.foreach(w1 =>
    words.foreach(w2 =>
      table = table ::: List((w1, w2))))


  val grouppedPairs = table.groupBy(self)
  val size = int2double(grouppedPairs.size)
  return grouppedPairs.mapValues(_.length / size)
}

Now, I fully realise that this self() trick is a dirty hack. So I thought a little a came out with a:

grouppedPairs = table groupBy (x => x)

This way it produced what I want. However, I still feel that I clearly miss something and there should be easier way of doing it. Any ideas at all, dear all?

Also, if you'd help me to improve the pairs extraction part, it'll also help a lot – it looks very imperative, C++ - ish right now. Many thanks in advance!

scala
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