bot.py

import random
from textblob import TextBlob
from textblob.np_extractors import ConllExtractor
extractor = ConllExtractor()

def main():   
    print("Hello, I am Marvin, the friendly robot.")
    print("You can end this conversation at any time by typing 'bye'")    
    print("After typing each answer, press 'enter'")
    print("How are you today?")

    while True:
        # wait for the user to enter some text
        user_input = input("> ")

        if user_input.lower() == "bye":            
            # if they typed in 'bye' (or even BYE, ByE, byE etc.), break out of the loop
            break
        else:
            # Create a TextBlob based on the user input. Then extract the noun phrases
            user_input_blob = TextBlob(user_input, np_extractor=extractor)                        
            np = user_input_blob.noun_phrases                                    
            response = ""
            if user_input_blob.polarity <= -0.5:
                response = "Oh dear, that sounds bad. "
            elif user_input_blob.polarity <= 0:
                response = "Hmm, that's not great. "
            elif user_input_blob.polarity <= 0.5:
                response = "Well, that sounds positive. "
            elif user_input_blob.polarity <= 1:
                response = "Wow, that sounds great. "

            if len(np) != 0:
                # There was at least one noun phrase detected, so ask about that and pluralise it
                # e.g. cat -> cats or mouse -> mice
                response = response + "Can you tell me more about " + np[0].pluralize() + "?"
            else:
                response = response + "Can you tell me more?"
            print(response)
    
    print("It was nice talking to you, goodbye!")

# Start the program
main()