def bow(sentence, words, show_details=false)
	    #tokenize the pattern
	    sentence_words=clean_up_sentence(sentence)
	    #bag of words
	    bag=[0] * words.size
	    # for s in sentence_words:
	    sentence_words.each do |s|        
	        words.each_with_index do |w,i|
	            if w == s
	                bag[i] = 1
	                if show_details
	                    puts "found in bag: #{w}"
	                end
	            end
	        end
	    end
	    # return Numo::Narray.new(bag)
	    return Numo::DFloat[bag].flatten
	end
def bow(sentence, words, show_details=false)
	    #tokenize the pattern
	    sentence_words=clean_up_sentence(sentence)
	    #bag of words
	    bag=[0] * words.size
	    # for s in sentence_words:
	    sentence_words.each do |s|        
	        words.each_with_index do |w,i|
	            if w == s
	                bag[i] = 1
	                if show_details
	                    puts "found in bag: #{w}"
	                end
	            end
	        end
	    end
	    # return Numo::Narray.new(bag)
	    return Numo::DFloat[bag].flatten
	end
return bag of words array: 0 or 1 for each word in the bag that exists in the sentence