Logic Adapters

Logic adapters determine the logic for how ChatterBot selects a response to a given input statement.

The logic adapter that your bot uses can be specified by setting the logic_adapters parameter to the import path of the logic adapter you want to use.

chatbot = ChatBot(
    "My ChatterBot",
    logic_adapters=[
        "chatterbot.logic.BestMatch"
    ]
)

It is possible to enter any number of logic adapters for your bot to use. If multiple adapters are used, then the bot will return the response with the highest calculated confidence value. If multiple adapters return the same confidence, then the adapter that is entered into the list first will take priority.

ChatterBot dialog processing flow

Common logic adapter attributes

Each logic adapter inherits the following attributes and methods.

Best Match Adapter

The BestMatch logic adapter selects a response based on the best known match to a given statement.

How it works

The best match adapter uses a function to compare the input statement to known statements. Once it finds the closest match to the input statement, it uses another function to select one of the known responses to that statement.

Setting parameters

chatbot = ChatBot(
    "My ChatterBot",
    logic_adapters=[
        {
            "import_path": "chatterbot.logic.BestMatch",
            "statement_comparison_function": chatterbot.comparisons.LevenshteinDistance,
            "response_selection_method": chatterbot.response_selection.get_first_response
        }
    ]
)

Note

The values for response_selection_method and statement_comparison_function can be a string of the path to the function, or a callable.

See the Statement comparison documentation for the list of functions included with ChatterBot.

See the Response selection methods documentation for the list of response selection methods included with ChatterBot.

Time Logic Adapter

The TimeLogicAdapter identifies statements in which a question about the current time is asked. If a matching question is detected, then a response containing the current time is returned.

User: What time is it?
Bot: The current time is 4:45PM.

Mathematical Evaluation Adapter

The MathematicalEvaluation logic adapter checks a given statement to see if it contains a mathematical expression that can be evaluated. If one exists, then it returns a response containing the result. This adapter is able to handle any combination of word and numeric operators.

User: What is four plus four?
Bot: (4 + 4) = 8

Specific Response Adapter

If the input that the chat bot receives, matches the input text specified for this adapter, the specified response will be returned.

Specific response example

from chatterbot import ChatBot


# Create a new instance of a ChatBot
bot = ChatBot(
    'Exact Response Example Bot',
    storage_adapter='chatterbot.storage.SQLStorageAdapter',
    logic_adapters=[
        {
            'import_path': 'chatterbot.logic.BestMatch'
        },
        {
            'import_path': 'chatterbot.logic.SpecificResponseAdapter',
            'input_text': 'Help me!',
            'output_text': 'Ok, here is a link: http://chatterbot.rtfd.org'
        }
    ]
)

# Get a response given the specific input
response = bot.get_response('Help me!')
print(response)

Low confidence response example

from chatterbot import ChatBot
from chatterbot.trainers import ListTrainer


# Create a new instance of a ChatBot
bot = ChatBot(
    'Example Bot',
    storage_adapter='chatterbot.storage.SQLStorageAdapter',
    logic_adapters=[
        {
            'import_path': 'chatterbot.logic.BestMatch',
            'default_response': 'I am sorry, but I do not understand.',
            'maximum_similarity_threshold': 0.90
        }
    ]
)

trainer = ListTrainer(bot)

# Train the chat bot with a few responses
trainer.train([
    'How can I help you?',
    'I want to create a chat bot',
    'Have you read the documentation?',
    'No, I have not',
    'This should help get you started: http://chatterbot.rtfd.org/en/latest/quickstart.html'
])

# Get a response for some unexpected input
response = bot.get_response('How do I make an omelette?')
print(response)