nfa.py 文件源码

def remove_state(self, state: str) -> None:
        """ Removes a state """
        # may not remove initial state
        if state != self._initial_state:
            self._states.discard(state)
            self._final_states.discard(state)

            for symbol in self._alphabet:
                # remove useless transitions that come from the removed state
                if (state, symbol) in self._transitions:
                    del self._transitions[state, symbol]

            empty_transitions = set()  # type Set[Tuple[str, str]]
            for actual_state, next_state in self._transitions.items():
                # remove transitions that go to the removed state
                next_state.discard(state)
                if not next_state:
                    empty_transitions.add(actual_state)

            for transition in empty_transitions:
                del self._transitions[transition]