Ruby Statistic Classifier

gistfile1.rb

class Classifier
  attr_accessor :training_sets, :noise_words

  def initialize(data)
    @training_sets = {}
    filename = File.join(File.dirname(__FILE__), 'stop_words.txt')
    @noise_words = File.new(filename).readlines.map(&:chomp)
    train_data(data)
  end

  def scores(text)
    words = text.downcase.scan(/[a-z]+/)

    scores = {}
    training_sets.each_pair do |category, word_weights|
      scores[category] = score(word_weights, words)
    end

    scores
  end

  def train_data(data)
    data.each_pair do |category, text|
      words = text.downcase.scan(/[a-z]+/)
      word_weights = Hash.new(0)

      words.each {|word| word_weights[word] += 1 unless noise_words.index(word)}

      ratio = 1.0 / words.length
      word_weights.keys.each {|key| word_weights[key] *= ratio}

      training_sets[category] = word_weights
    end
  end

  private
    def score(word_weights, words)
      score = words.inject(0) {|acc, word| acc + word_weights[word]}
      1000.0 * score / words.size
    end
end