Finds a normalized ranking of word frequency given an article of text

normalized_word_frequency.rb

##
# Finds a normalized ranking of word frequency given an article of text
#
class Hash
  ##
  # Normalize the array to values between 0 and 1
  #
  # @param [Boolean] weight_lower_value Set to true to give more weight to lower values
  #
  def normalize(weight_lower_value = false)
    lower_bound = 0.00000001
    s = []
    if weight_lower_value
      min_val = self.values.min
      self.each do |k,v|
        z = min_val.to_f/([lower_bound,1].max)
        s << [k,z]
      end
    else
      max_val = self.values.max
      max_val = lower_bound if max_val == 0
      self.each do |k,v|
        s << [k,(v.to_f/max_val)]
      end
    end
    s
  end
end
class Array
  ##
  # Find a frequency hash of the words in this array
  #
  # @param [Array] exclude_words An array of words to exclude
  #
  def word_frequency(exclude_words = %w(the for and has))
    f = {}
    self.each do |w|
      next if w.to_i > 0 or w.length < 3 or exclude_words.include?(w)
      if f[w.to_s]
        f[w.to_s] = f[w.to_s] + 1
      else
        f[w.to_s] = 1
      end
    end
    f
  end
end

file = ARGV[0] ? ARGV[0].to_s : "article.txt"
words = File.read(file).scan(/\w+/)
puts words.word_frequency.normalize.sort_by {|k,v| v}.inspect