alfred.py

# https://medium.com/analytics-vidhya/building-a-simple-chatbot-in-python-using-nltk-7c8c8215ac6e

import random
import string  # to process standard python strings
import warnings

from sklearn.feature_extraction.text import TfidfVectorizer
from sklearn.metrics.pairwise import cosine_similarity


import nltk
from nltk.stem import WordNetLemmatizer

warnings.filterwarnings("ignore")

nltk.download('popular', quiet=True)  # for downloading packages
# Includes the following already.
# nltk.download('punkt') # first-time use only
# nltk.download('wordnet') # first-time use only

with open('alfred-knowledge-base.txt', 'r', encoding='utf8', errors='ignore') as fin:
    raw = fin.read().lower()

sent_tokens = nltk.sent_tokenize(raw)  # converts to list of sentences
word_tokens = nltk.word_tokenize(raw)  # converts to list of words

lemmer = WordNetLemmatizer()


def LemTokens(tokens):
    return [lemmer.lemmatize(token) for token in tokens]


remove_punct_dict = dict((ord(punct), None) for punct in string.punctuation)


def LemNormalize(text):
    return LemTokens(nltk.word_tokenize(text.lower().translate(remove_punct_dict)))


GREETING_INPUTS = ("hello", "hi", "greetings", "sup", "what's up", "hey")
GREETING_RESPONSES = ["hi", "hey", "*nods*", "hi there", "hello", "I am glad! You are talking to me"]


# Checking for greetings
def greeting(sentence):
    """If user's input is a greeting, return a greeting response"""
    for word in sentence.split():
        if word.lower() in GREETING_INPUTS:
            return random.choice(GREETING_RESPONSES)


# Generating response
def response(user_response):
    robo_response = ''
    sent_tokens.append(user_response)
    TfidfVec = TfidfVectorizer(tokenizer=LemNormalize, stop_words='english')
    tfidf = TfidfVec.fit_transform(sent_tokens)
    vals = cosine_similarity(tfidf[-1], tfidf)
    idx = vals.argsort()[0][-2]
    flat = vals.flatten()
    flat.sort()
    req_tfidf = flat[-2]
    if (req_tfidf == 0):
        robo_response = robo_response + "I am sorry! I don't understand you"
        return robo_response
    else:
        robo_response = robo_response + sent_tokens[idx]
        return robo_response


flag = True
print("Alfred: My name is Alfred. I will answer your queries about Chatbots. If you want to exit, type Bye!")

while (flag == True):
    user_response = input()
    user_response = user_response.lower()
    if (user_response != 'bye'):
        if (user_response == 'thanks' or user_response == 'thank you'):
            flag = False
            print("Alfred: You are welcome..")
        else:
            if (greeting(user_response) != None):
                print("Alfred: " + greeting(user_response))
            else:
                print("Alfred: ", end="")
                print(response(user_response))
                sent_tokens.remove(user_response)
    else:
        flag = False
        print("Alfred: Bye! take care..")