为什么列表中的第一个位置不变？

Question

在这个小的交通模拟系统中，列表中的第一个位置不会改变，你可以看到：

[.....], (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.]

我试图让“目的地S”定义的汽车也出现在第一个位置，就像

[.....] (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.]   []

类目的地是模拟新车辆到达交通系统的过程。对其step方法的每个调用都返回None，表示没有车辆到达该步骤，或者返回目的地('W‘或'S')，这个类被传递给我，我不允许更改它，如果有人能为我解释它，我不明白它到底是如何工作的。

类交通灯表示交通信号。

类车道是一种包含大量车辆和许多空空间的结构。车辆只可在行车线开始时驶入，而在行车线尽头离开，即行车线就象一条“管子”。

类车辆它的任务只是跟踪车辆创建的时间和它要去的地方。

Class TrafficSystem定义了特定的流量系统。它跟踪哪些车道、哪些信号以及车辆将如何通过它拥有的系统进行移动：

1. 创建组件的构造函数.

一个方法步骤()，它将所有组件向前推进一步，将车辆移进或移出系统，通过信号灯和车道之间，就像this

• Remove --图中的第一(左)车道上的第一辆车一样。-步进第一车道及其步进法。-如果信号是绿色的，将第一辆车从第二(右)车道移至第一车道。-按其步进法对交通信号进行步进。-走第二车道。-调用Destinations对象中的step方法--如果返回一个目标(即没有其他的内容)，那么创建一个车辆并将其放在第二车道上。

1. --一个打印系统快照的方法快照()，它应该基于来自各个组件的str()方法。

4.返回系统中当前车辆总数的number_in_system()方法。

5.打印一些统计数据的方法print_statistics()。

守则是：

class Destinations:
    """ Generates a sequence of destinations (None, 'W', 'S') """

    def __init__(self):
        self._arrivals = (  # 0:52, 1:26, 2:22
            2, 2, 2, 2, 2, 1, 2, 2, 2, 1, 1, 2, 1, 2, 2, 2, 1, 2, 1, 1,
            2, 1, 1, 0, 2, 0, 0, 0, 0, 1, 2, 0, 0, 0, 1, 0, 0, 2, 0, 1,
            2, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1,
            0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 2, 0, 0,
            1, 2, 0, 1, 0, 2, 0, 2, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1)

        self._internal_time = 0
        self._total_cycle = len(self._arrivals)

    def step(self):
        ind = self._arrivals[self._internal_time]
        self._internal_time = (self._internal_time + 1) % len(self._arrivals)
        return 'W' if ind == 1 else 'S' if ind == 2 else None
# Traffic system components
class Vehicle:
    '''Represents vehicles in traffic simulations
    '''

    def __init__(self, destination, borntime):
        self.destination = destination
        self.borntime = borntime

    def __repr__(self):
        '''A verbose representation
        '''
        return f'Vehicle({self.destination}, {self.borntime})'

    def __str__(self):
        '''A simple representation
        '''
        return self.destination


class Light:
    """Represents a traffic light"""

    def __init__(self, period, green_period):
        self.period = period
        self.green_period = green_period
        self.color = 'G'
        self.time = 0

    def __str__(self):
        return f"({self.color})"

    def step(self):
        self.time += 1
        if self.time % self.period < self.green_period:
            self.color = 'G'
        else: 
            self.color = 'R'

    def is_green(self):
        if self.color == 'G':
            return True
        elif self.color == 'R':
            return False


class Lane:
    '''Represents a lane with (possible) vehicles
    '''

    def __init__(self, length):
        self.length = length
        self.lane = ['.'] * self.length

    def __str__(self):
        '''Lane representation
        '''
        return '[' + ''.join([str(s) for s in self.lane]) + ']'

    def enter(self, vehicle):
        self.lane[-1] = vehicle

    def is_last_free(self):
        return self.lane[-1] == '.'

    def step(self):
        '''Implementation of step
        '''
        for i in range(len(self.lane) - 1):
            if self.lane[i] == '.':  # if a spot is empty
                self.lane[i] = self.lane[i + 1]  # move next spot forward
                self.lane[i + 1] = '.'  # and clear next spot
        self.lane[-1] = '.'  # clear the very last spot

    def get_first(self):
        if self.lane[0] == '.':
            return None
        else:
            return self.lane[0]

    def remove_first(self):
        x = self.lane[0]
        if x == '.':
            return None
        else:
            self.lane[0] = '.'
            return x

    def number_in_lane(self):
        return len(self.lane) - self.lane.count('.')

from statistics import mean, median
from time import sleep
import destinations as ds
import trafficComponents as tc


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):
        v = tc.Vehicle(str(self.destinations.step()),10)
        self.lane_1.remove_first()
        if self.light.is_green:
            self.lane_2.enter(v)
            self.lane_2.step()
            if self.lane_2.get_first() != None:
                self.lane_1.enter(self.lane_2.remove_first())
                self.lane_1.step()
                self.lane_1.remove_first()
       
        

    def in_system(self):
        pass

    def print_statistics(self):
        pass


def main():
    ts = TrafficSystem()
    for i in range(20):
        ts.snapshot()
        ts.step()
        sleep(0.1)
    print('\nFinal state:')
    ts.snapshot()
    print()
    ts.print_statistics()


if __name__ == '__main__':
    main()

Answer 1

我的错误是在步骤()方法中排序赞扬。

守则是：

def step(self):
        self.time += 1
        self.lane_1.remove_first()
        self.lane_1.step()
        if self.light.is_green():
            self.lane_1.enter(self.lane_2.remove_first())
        self.light.step()
        self.lane_2.step()
        self.destinations.step()
        x = self.destinations.step()
        if x != None:
            v = tc.Vehicle(x, self.time)
            self.lane_2.enter(v)

我将循环范围更改为100。

结果是：

[.....], (G), [.....]
[.....], (G), [....S]
[.....], (G), [...SS]
[.....], (G), [..SSW]
[.....], (G), [.SSWS]
[.....], (G), [SSWSW]
[....S], (G), [SWSWS]
[...SS], (G), [WSWSS]
[..SSW], (R), [SWSSS]
[.SSW.], (R), [SWSSS]
[SSW..], (G), [SWSSW]
[SW..S], (G), [WSSWW]
[W..SW], (G), [SSWW.]
[..SWS], (G), [SWW..]
[.SWSS], (G), [WW...]
[SWSSW], (G), [W...W]
[WSSWW], (G), [...W.]
[SSWW.], (G), [..W..]
[SWW..], (R), [.W...]
[WW...], (R), [W...S]
[W....], (G), [W..SW]
[....W], (G), [..SW.]
[...W.], (G), [.SW..]
[..W..], (G), [SW...]
[.W..S], (G), [W....]
[W..SW], (G), [....W]
[..SW.], (G), [...W.]
[.SW..], (G), [..W.W]
[SW...], (R), [.W.W.]
[W....], (R), [W.W.W]
[.....], (G), [WW.WW]
[....W], (G), [W.WWW]
[...WW], (G), [.WWW.]
[..WW.], (G), [WWW..]
[.WW.W], (G), [WW..W]
[WW.WW], (G), [W..W.]
[W.WWW], (G), [..W.W]
[.WWW.], (G), [.W.W.]
[WWW..], (R), [W.W.W]
[WW...], (R), [WW.WS]
[W....], (G), [WWWS.]
[....W], (G), [WWS.S]
[...WW], (G), [WS.SW]
[..WWW], (G), [S.SWS]
[.WWWS], (G), [.SWSS]
[WWWS.], (G), [SWSS.]
[WWS.S], (G), [WSS..]
[WS.SW], (G), [SS...]
[S.SWS], (R), [S....]
[.SWS.], (R), [S....]
[SWS..], (G), [S...W]
[WS..S], (G), [...WS]
[S..S.], (G), [..WSS]
[..S..], (G), [.WSSW]
[.S...], (G), [WSSWS]
[S...W], (G), [SSWSW]
[...WS], (G), [SWSWS]
[..WSS], (G), [WSWSS]
[.WSSW], (R), [SWSSS]
[WSSW.], (R), [SWSSS]
[SSW..], (G), [SWSSW]
[SW..S], (G), [WSSWW]
[W..SW], (G), [SSWW.]
[..SWS], (G), [SWW..]
[.SWSS], (G), [WW...]
[SWSSW], (G), [W...W]
[WSSWW], (G), [...W.]
[SSWW.], (G), [..W..]
[SWW..], (R), [.W...]
[WW...], (R), [W...S]
[W....], (G), [W..SW]
[....W], (G), [..SW.]
[...W.], (G), [.SW..]
[..W..], (G), [SW...]
[.W..S], (G), [W....]
[W..SW], (G), [....W]
[..SW.], (G), [...W.]
[.SW..], (G), [..W.W]
[SW...], (R), [.W.W.]
[W....], (R), [W.W.W]
[.....], (G), [WW.WW]
[....W], (G), [W.WWW]
[...WW], (G), [.WWW.]
[..WW.], (G), [WWW..]
[.WW.W], (G), [WW..W]
[WW.WW], (G), [W..W.]
[W.WWW], (G), [..W.W]
[.WWW.], (G), [.W.W.]
[WWW..], (R), [W.W.W]
[WW...], (R), [WW.WS]
[W....], (G), [WWWS.]
[....W], (G), [WWS.S]
[...WW], (G), [WS.SW]
[..WWW], (G), [S.SWS]
[.WWWS], (G), [.SWSS]
[WWWS.], (G), [SWSS.]
[WWS.S], (G), [WSS..]
[WS.SW], (G), [SS...]
[S.SWS], (R), [S....]
[.SWS.], (R), [S....]

Final state:
[SWS..], (G), [S...W]

Answer 2

TrafficSystem.step()总是从lane_1中移除第一个位置。

    def step(self):
        v = tc.Vehicle(str(self.destinations.step()),10)
        self.lane_1.remove_first()
        if self.light.is_green:
            self.lane_2.enter(v)
            self.lane_2.step()
            if self.lane_2.get_first() != None:
                self.lane_1.enter(self.lane_2.remove_first())
                self.lane_1.step()
                self.lane_1.remove_first()

它做的第一件事是self.lane_1.remove_first()，它移除第一个元素。

然后，如果lane_2的第一个元素不是None，它会将第一个元素移动到lane_1，步骤1，然后再次删除第一个元素。

因此，不管条件如何，它对self.lane_1所做的最后一件事就是remove_first()。

我不明白模拟，所以我不知道你应该做什么来修复它。您需要找出真正需要调用remove_first()的时间。