Class: Sentiments::Classifier

Inherits:
Object
  • Object
show all
Defined in:
lib/sentiments.rb

Constant Summary collapse

MIN_TOKEN_LENGTH = 
1
MAX_TOKEN_LENGTH = 
15
PRIOR_SCORE = 
0.33

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Classifier

Returns a new instance of Classifier.



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# File 'lib/sentiments.rb', line 8

def initialize
  # @neg_words    = load_json('neg')
  # @pos_words    = load_json('pos')
  # @neu_words    = load_json('neu')
  @prefix_words = load_json('prefix')
  @ignore_words = load_json('ignore')

  @categories = ['pos', 'neg', 'neu']

  @dictionary = {}
  @doc_count = 0
  @token_count = 0
  @category_tok_count = {'pos' => 0, 'neg' => 0, 'neu' => 0}
  @category_doc_count = {'pos' => 0, 'neg' => 0, 'neu' => 0}

  @categories.each do |category|
    if (!set_dictionary(category))
      raise "Unable to Set Dictionaries"
    end #if
  end

end

Instance Method Details

#score(sentence) ⇒ Object

initialize



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# File 'lib/sentiments.rb', line 31

def score(sentence)
  scores = {}
  @prefix_words.each do |pw|
    # Search if that prefix is in the sentence
    if sentence.index(pw)
      # Remove the white space after the negative prefix
      sentence.sub! pw+" ", pw
    end
  end
  tokens = tokenize(sentence)
  total_score = 0

  @categories.each do |category|
    scores[category] = 1
    tokens.each do |token|
      if (token.length > MIN_TOKEN_LENGTH && token.length < MAX_TOKEN_LENGTH && !(@ignore_words.include? token))

        # If Token is not in our dictionary, don't do anything
        if(@dictionary[token].nil?)
          break
        end #if

        if (@dictionary[token][category].nil?)
          count = 0
        else
          count = @dictionary[token][category]
        end # elseif
        scores[category] *= (count + 1)
      end #if
    end #tokens
    scores[category] = PRIOR_SCORE * scores[category]
  end #categories

  @categories.each do |category|
    total_score += scores[category]
  end #categories

  @categories.each do |category|
    scores[category] = scores[category]/total_score
  end #categories

  return scores
end