How do Markov Chain Chatbots work?

Question

I was thinking of creating a chatbot using something like markov chains, but I\'m not entirely sure how to get it to work. From what I understand, you create a table from data w

Answer 1

The bot chooses a random word from your input and generates a response by choosing another random word that has been seen to be a successor to its held word. It then repeats the process by finding a successor to that word in turn and carrying on iteratively until it thinks it’s said enough. It reaches that conclusion by stopping at a word that was prior to a punctuation mark in the training text. It then returns to input mode again to let you respond, and so on.

It isn’t very realistic but I hereby challenge anyone to do better in 71 lines of code !! This is a great challenge for any budding Pythonists, and I just wish I could open the challenge to a wider audience than the small number of visitors I get to this blog. To code a bot that is always guaranteed to be grammatical must surely be closer to several hundred lines, I simplified hugely by just trying to think of the simplest rule to give the computer a mere stab at having something to say.

Its responses are rather impressionistic to say the least ! Also you have to put what you say in single quotes.

I used War and Peace for my “corpus” which took a couple of hours for the training run, use a shorter file if you are impatient…

here is the trainer

#lukebot-trainer.py
import pickle
b=open('war&peace.txt')
text=[]
for line in b:
    for word in line.split():
        text.append (word)
b.close()
textset=list(set(text))
follow={}
for l in range(len(textset)):
    working=[]
    check=textset[l]
    for w in range(len(text)-1):
        if check==text[w] and text[w][-1] not in '(),.?!':
            working.append(str(text[w+1]))
    follow[check]=working
a=open('lexicon-luke','wb')
pickle.dump(follow,a,2)
a.close()

Here is the bot:

#lukebot.py
import pickle,random
a=open('lexicon-luke','rb')
successorlist=pickle.load(a)
a.close()
def nextword(a):
    if a in successorlist:
        return random.choice(successorlist[a])
    else:
        return 'the'
speech=''
while speech!='quit':
    speech=raw_input('>')
    s=random.choice(speech.split())
    response=''
    while True:
        neword=nextword(s)
        response+=' '+neword
        s=neword
        if neword[-1] in ',?!.':
            break
    print response

You tend to get an uncanny feeling when it says something that seems partially to make sense.