gistfile1.rb

class Hash
  def symbolize_keys!
    self.each do |key, val|
      self.delete(key)

      if val.is_a? Hash
        self[key.to_sym] = val.symbolyze_keys
      elsif val.is_a? Array
        self[key.to_sym] = val.map{|el| el.symbolyze_keys}
      else
        self[key.to_sym] = val
      end
    end
  end

  def symbolize_keys
    self.clone.symbolyze_keys!
  end
end