Class: NounPhraseDetector

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

Constant Summary collapse

ADJECTIVE =

adjective, advective comparative, advective superlative

%w{JJ JJR JJS}
NOUN =

noun, noun plural, proper noun, proper noun plural

%w{NN NNS NNP NNPS}
PREPOSITION = 
%w{TO}

Instance Method Summary collapse

Constructor Details

#initialize(text, lexicon_path) ⇒ NounPhraseDetector

Returns a new instance of NounPhraseDetector.



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# File 'lib/noun_phrase_detector.rb', line 9

def initialize(text, lexicon_path)
  @words = []
  @pos = []
  analyze_part_of_speech(text, lexicon_path)
end

Instance Method Details

#count_noun_phrases ⇒ Object 



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# File 'lib/noun_phrase_detector.rb', line 49

def count_noun_phrases
  noun_phrases = extract_all_noun_phrases
  phrase_counts = Hash.new {|hash,k| hash[k] = 0}
  
  noun_phrases.each do |phrase|
    phrase_counts[phrase] += 1
  end
  
  phrase_counts
end

#extract_all_noun_phrases ⇒ Object

Basic noun phrases pattern (Adjective | Noun)* (Noun Preposition)? (Adjective | Noun)* Noun



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# File 'lib/noun_phrase_detector.rb', line 17

def extract_all_noun_phrases
  phrases = []
  
  # We are going to start with noun on the furthest right
  # and work our way to the left
  @pos.each_with_index do |word, index|
    next unless NOUN.include?(word)
    
    phrase = [index]
    i = index
    
    until i == 0
      i -= 1
      
      if i != 0 && NOUN.include?(@pos[i]) && PREPOSITION.include?(@pos[i-1])
        phrase.unshift(i-1)
        phrase.unshift(i)
      elsif NOUN.include?(@pos[i]) || ADJECTIVE.include?(@pos[i])
        phrase.unshift(i)
      else
        break
      end
    end
    
    phrases << phrase
  end
  
  phrases.map do |x|
    x.map {|i| @words[i]}.join(' ')
  end
end