spam-filter-challenge.txt

Here's a challenge for our next meeting.

A Bayesian spam filter has a surprisingly simple structure. In this challenge,
you write the Scala code to train a spam filter and run it on some training
examples.

This exercise is inspired by the free online AI class now being given at
Stanford University (http://ai-class.com). Enrollment is closed, but you can
find the class videos related to this challenge starting at:

  https://www.ai-class.com/course/video/quizquestion/90

This challenge has two levels. The harder version (Spam-hard.scala) is a
skeleton that requires you to finish two things:

1. The code that digests the training examples (to test your knowledge of Scala
   collections).
2. The spam classifier itself (to test your knowledge of the material in the AI
   class videos).

The easier version (Spam-easy.scala) has part 2 already completed, so that you
need complete only part 1.

Note that the scala.io package is less polished than most of the standard Scala
libraries. It's sufficient for this exercise, but I think the Scala team would
like to rewrite it.