交通模拟系统左侧车道首位无更新问题及代码修正咨询

问题现象 #

运行时左侧车道（lane_1）首位始终无车辆更新，运行快照如下：

[.....], (G), [.....]
[.....], (G), [...S.]
[.....], (G), [..SS.]
[.....], (G), [.SSS.]
[...S.], (G), [.SSS.]
[..SS.], (G), [.SSS.]
[.SSS.], (G), [.SSW.]
[.SSS.], (G), [.SWS.]
[.SSS.], (G), [.WSS.]
[.SSW.], (G), [.SSS.]
[.SWS.], (G), [.SSW.]
[.WSS.], (G), [.SWW.]
[.SSS.], (G), [.WWS.]
[.SSW.], (G), [.WSW.]
[.SWW.], (G), [.SWS.]
[.WWS.], (G), [.WSS.]
[.WSW.], (G), [.SSS.]
[.SWS.], (G), [.SSW.]
[.WSS.], (G), [.SWS.]
[.SSS.], (G), [.WSW.]

Final state:
[.SSW.], (G), [.SWW.]

预期效果 #

期望目的地为'S'的车辆能出现在左侧车道首位，预期运行效果如下：

[.....] (G) [.....]   []
    [.....] (G) [....S]   []
    [.....] (G) [...SS]   []
    [.....] (G) [..SSS]   []
    [.....] (G) [.SSSS]   []
    [.....] (G) [SSSSS]   []
    [....S] (G) [SSSSW]   []
    [...SS] (G) [SSSWS]   []
    [..SSS] (R) [SSWSS]   []
    [.SSS.] (R) [SSWSS]   ['S']
    [SSS..] (G) [SSWSS]   ['S', 'W']
    [SS..S] (G) [SWSSS]   ['W', 'W']
    [S..SS] (G) [WSSSW]   ['W', 'S']
    [..SSW] (G) [SSSWW]   ['S', 'W']
    [.SSWS] (G) [SSWWS]   ['W', 'S']
    [SSWSS] (G) [SWWSW]   ['S', 'S']
    [SWSSS] (G) [WWSWS]   ['S', 'S']
    [WSSSW] (G) [WSWSS]   ['S', 'W']
    [SSSWW] (R) [SWSSS]   ['W', 'S']
    [SSWW.] (R) [SWSSS]   ['W', 'S', 'W']
    [SWW..] (G) [SWSSS]   ['W', 'S', 'W', 'W']
    [WW..S] (G) [WSSSW]   ['S', 'W', 'W', 'S']
    [W..SW] (G) [SSSWS]   ['W', 'W', 'S', 'W']
    [..SWS] (G) [SSWSW]   ['W', 'S', 'W', 'W']
    [.SWSS] (G) [SWSWW]   ['S', 'W', 'W']
    [SWSSS] (G) [WSWWS]   ['W', 'W', 'S']
    [WSSSW] (G) [SWWSW]   ['W', 'S']
    [SSSWS] (G) [WWSWW]   ['S']
    [SSWSW] (R) [WSWWS]   []
    [SWSW.] (R) [WSWWS]   []
    [WSW..] (G) [WSWWS]   ['W']
    [SW..W] (G) [SWWSW]   ['S']
    [W..WS] (G) [WWSWS]   []
    [..WSW] (G) [WSWS.]   []

Destinations类工作逻辑 #

该类负责生成固定序列的车辆目的地，逻辑如下：

• 初始化时定义了一个长度为100的元组_arrivals，其中：
  • 0代表本次无车辆生成
  • 1代表生成目的地为'W'的车辆
  • 2代表生成目的地为'S'的车辆
• _internal_time作为内部计数器，记录当前使用序列的索引位置
• step()方法每次执行时：
  1. 获取当前_internal_time对应的_arrivals元素值
  2. 将_internal_time加1，超过序列长度时取模循环
  3. 根据元素值返回对应目的地：1返回'W'，2返回'S'，0返回None

修正TrafficSystem的step方法 #

原step方法逻辑混乱，未遵循指定流程，且存在调用is_green时未加括号的错误（self.light.is_green是方法引用，需改为self.light.is_green()）。以下是遵循指定流程修正后的step方法：

修正后的TrafficSystem类 #

class TrafficSystem:
    """Defines a traffic system"""

    def __init__(self):
        self.time = 0
        self.destinations = ds.Destinations()
        self.lane_1 = tc.Lane(5)
        self.lane_2 = tc.Lane(5)
        self.light = tc.Light(10, 8)

    def snapshot(self):
        print(
            f"{self.lane_1.__str__()}, {self.light.__str__()}, {self.lane_2.__str__()}")

    def step(self):
        # 1. 移除左侧车道的首位车辆
        self.lane_1.remove_first()
        # 2. 调用左侧车道的step方法
        self.lane_1.step()
        # 3. 若信号灯为绿色，将右侧车道的首位车辆移至左侧车道
        if self.light.is_green():
            first_vehicle = self.lane_2.remove_first()
            if first_vehicle is not None:
                self.lane_1.enter(first_vehicle)
        # 4. 调用信号灯的step方法
        self.light.step()
        # 5. 调用右侧车道的step方法
        self.lane_2.step()
        # 6. 调用Destinations的step方法，若返回目的地则创建车辆并加入右侧车道末尾
        dest = self.destinations.step()
        if dest is not None:
            new_vehicle = tc.Vehicle(dest, self.time)
            self.lane_2.enter(new_vehicle)
        # 更新系统时间
        self.time += 1

    def in_system(self):
        pass

    def print_statistics(self):
        pass

修正说明 #

• 严格按照指定的6步流程执行，确保每一步顺序正确
• 修复了is_green的调用错误，改为调用方法self.light.is_green()
• 新增系统时间self.time作为车辆的borntime，符合Vehicle类的初始化要求
• 处理右侧车道移车时的空值情况，避免将None加入左侧车道

内容的提问来源于stack exchange，提问作者user17079709