Source code for chatterbot.logic.mathematical_evaluation

from chatterbot.logic import LogicAdapter
from chatterbot.conversation import Statement
from chatterbot import languages

[docs]class MathematicalEvaluation(LogicAdapter): """ The MathematicalEvaluation logic adapter parses input to determine whether the user is asking a question that requires math to be done. If so, the equation is extracted from the input and returned with the evaluated result. For example: User: 'What is three plus five?' Bot: 'Three plus five equals eight' :kwargs: * *language* (``object``) -- The language is set to ``chatterbot.languages.ENG`` for English by default. """ def __init__(self, chatbot, **kwargs): super().__init__(chatbot, **kwargs) self.language = kwargs.get('language', languages.ENG) self.cache = {} def can_process(self, statement): """ Determines whether it is appropriate for this adapter to respond to the user input. """ response = self.process(statement) self.cache[statement.text] = response return response.confidence == 1 def process(self, statement, additional_response_selection_parameters=None): """ Takes a statement string. Returns the equation from the statement with the mathematical terms solved. """ from mathparse import mathparse input_text = statement.text # Use the result cached by the process method if it exists if input_text in self.cache: cached_result = self.cache[input_text] self.cache = {} return cached_result # Getting the mathematical terms within the input statement expression = mathparse.extract_expression(input_text, language=self.language.ISO_639.upper()) response = Statement(text=expression) try: response.text = '{} = {}'.format( response.text, mathparse.parse(expression, language=self.language.ISO_639.upper()) ) # The confidence is 1 if the expression could be evaluated response.confidence = 1 except mathparse.PostfixTokenEvaluationException: response.confidence = 0 return response