Class: MarkovSentenceGenerator

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

Instance Method Summary collapse

Constructor Details

#initialize(dictionary) ⇒ MarkovSentenceGenerator

:nodoc:



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# File 'lib/marky_markov/markov_sentence_generator.rb', line 24

def initialize(dictionary)
  @dictionary = dictionary
  @depth = @dictionary.depth
end

Instance Method Details

#generate(wordcount) ⇒ String

Generates a sentence of (wordcount) length using the weighted_random function.

Parameters:

  • wordcount (Int) —

    The number of words you want the generated string to contain.

Returns:

  • (String) —

    the words, hopefully forming sentences generated.



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# File 'lib/marky_markov/markov_sentence_generator.rb', line 75

def generate(wordcount)
  if @dictionary.dictionary.empty?
    raise EmptyDictionaryError.new("The dictionary is empty! Parse a source file/string!")
  end
  sentence = []
  sentence.concat(random_capitalized_word)
  (wordcount-1).times do
    word = weighted_random(sentence.last(@depth))
    if punctuation?(word)
      sentence[-1] = sentence.last.dup << word
      sentence.concat(random_capitalized_word)
    elsif word.nil?
      sentence.concat(random_capitalized_word)
    else
      sentence << word
    end
  end
  sentence.pop(sentence.length-wordcount)
  sentence.join(' ')
end

#generate_sentence(sentencecount) ⇒ String

Generates a (sentencecount) sentences using the weighted_random function.

Parameters:

  • sentencecount (Int) —

    The number of sentences you want the generated string to contain.

Returns:

  • (String) —

    the sentence(s) generated.



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# File 'lib/marky_markov/markov_sentence_generator.rb', line 100

def generate_sentence(sentencecount)
  if @dictionary.dictionary.empty?
    raise EmptyDictionaryError.new("The dictionary is empty! Parse a source file/string!")
  end
  sentence = []
  # Find out how many actual keys are in the dictionary.
  key_count = @dictionary.dictionary.keys.length
  # If less than 30 keys, use that plus five as your maximum sentence length.
  maximum_length = key_count < 30 ? key_count + 5 : 30
  sentencecount.times do
    wordcount = 0
    sentence.concat(random_capitalized_word)
    until (punctuation?(sentence.last[-1])) || wordcount > maximum_length
      wordcount += 1
      word = weighted_random(sentence.last(@depth))
      if punctuation?(word)
        sentence[-1] = sentence.last.dup << word
      else
        sentence << word
      end
    end
  end
  sentence.join(' ')
end

#punctuation?(word) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/marky_markov/markov_sentence_generator.rb', line 67

def punctuation?(word)
  ( word =~ /[!?]/ || word == '.' )
end

#random_capitalized_word ⇒ Object

Generates a random capitalized word via picking a random key from the dictionary and recurring if the word is lowercase.

(see #random_word)



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# File 'lib/marky_markov/markov_sentence_generator.rb', line 44

def random_capitalized_word
  attempts = 0
  # If you don't find a capitalized word after 15 attempts, just use
  # a lowercase word as there may be no capitals in the dicationary.
  until attempts > 15
    attempts += 1
    words = @dictionary.dictionary.keys
    random_choice = words[rand(words.length)]
    if random_choice[0] =~ /[A-Z]/
      return random_choice
    end
  end
  random_word
end

#random_word ⇒ String

Returns a random word via picking a random key from the dictionary. In the case of the TwoWordDictionary, it returns two words to ensure that the sentence will have a valid two word string to pick the next word from. wordslength

Returns:

  • (String) —

    a string containing a random dictionary key.



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# File 'lib/marky_markov/markov_sentence_generator.rb', line 35

def random_word
  words = @dictionary.dictionary.keys
  words[rand(words.length)]
end

#weighted_random(lastword) ⇒ Object

Returns a word based upon the likelihood of it appearing after the supplied word.



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# File 'lib/marky_markov/markov_sentence_generator.rb', line 61

def weighted_random(lastword)
  # If word has no words in its dictionary (last word in source text file)
  # have it pick a random word to display instead.
  @dictionary.dictionary.fetch(lastword, NULL_OBJECT).sample
end