navigation.py 文件源码

def on_start(self, event):
        # choose a random object
        self.target_obj, = random.sample(objects, 1)
        ws = self.get_world().state
        # select a random number of steps
        self.n = random.randint(1, PickUpInFrontTask.max_steps_forward)
        # place the object that number of steps in front of the learner
        p = ws.learner_pos + self.n * self.get_world().valid_directions[
            ws.learner_direction]
        self.state.initial_count = ws.learner_inventory[self.target_obj]
        self.get_world().put_entity(p, self.target_obj, True, True)

        self.add_handler(
            on_state_changed(lambda ws, ts:
                             ws.learner_inventory[self.target_obj] ==
                             ts.initial_count + 1)
            (self.on_object_picked_up))

        self.set_message("There is {indef_object} {n} steps forward, "
                         "pick up the {object}."
                         .format(
                             indef_object=msg.indef_article(self.target_obj),
                             n=msg.number_to_string(self.n),
                             object=self.target_obj))