IndexError：列表索引超出范围

Question

我一直在尝试创建程序生成的地下城，如this article所示。但是这对我来说理解这种算法的工作有点难。相反，我一直在使用this作为指导，至少了解房间的位置。本文中使用的程序是用Java编写的，因此我对“现实”做了一些修改，并尝试在Python 3.5中模拟相同的结果。

我的代码如下：

from random import randint 


class Room: 

    """docstring for Room""" 

    def __init__(self, x, y, w, h): 
     """[summary] 

     [description] 

     Arguments: 
       x {int} -- bottom-left horizontal anchorpoint of the room 
       y {int} -- bottom-left vertical anchor point of the room 
       w {int} -- width of the room 
       h {int} -- height of the room 
     """ 
     self.x1 = x 
     self.x2 = x + w 
     self.y1 = y 
     self.y2 = y + h 
     self.w = w 
     self.h = h 
     self.center = ((self.x1 + self.x2)/2, (self.y1 + self.y2)/2) 

    def intersects(self, room): 
     """[summary] 

     Verifies if the rooms overlap 

     Arguments: 
       room {Room} -- a room object 
     """ 
     return(self.x1 <= room.x2 and self.x2 >= room.x1 and \ 
       self.y1 <= room.y2 and self.y2 >= room.y1) 

    def __str__(self): 
     room_info = ("Coords: (" + str(self.x1) + ", " + str(self.y1) + 
        ") | (" + str(self.x2) + ", " + str(self.y2) + ")\n") 
     room_info += ("Center: " + str(self.center) + "\n") 
     return(room_info) 

MIN_ROOM_SIZE = 10 
MAX_ROOM_SIZE = 20 
MAP_WIDTH = 400 
MAP_HEIGHT = 200 
MAX_NUMBER_ROOMS = 20 

dungeon_map = [[None] * MAP_WIDTH for i in range(MAP_HEIGHT)] 
# print(dungeon_map) 


def crave_room(room): 
    """[summary] 

    "saves" a room in the dungeon map by making everything inside it's limits 1 

    Arguments: 
      room {Room} -- the room to crave in the dungeon map 
    """ 
    for x in xrange(min(room.x1, room.x2), max(room.x1, room.x2) + 1): 
     for y in xrange(min(room.y1, room.y2), max(room.y1, room.y2) + 1): 
      print(x, y) # debug 
      dungeon_map[x][y] = 1 
    print("Done") # dungeon 


def place_rooms(): 

    rooms = [] 

    for i in xrange(0, MAX_NUMBER_ROOMS): 
     w = MIN_ROOM_SIZE + randint(0, MAX_ROOM_SIZE - MIN_ROOM_SIZE + 1) 
     h = MIN_ROOM_SIZE + randint(0, MAX_ROOM_SIZE - MIN_ROOM_SIZE + 1) 
     x = randint(0, MAP_WIDTH - w) + 1 
     y = randint(0, MAP_HEIGHT - h) + 1 

     new_room = Room(x, y, w, h) 
     fail = False 
     for other_room in rooms: 
      if new_room.intersects(other_room): 
       fail = True 
       break 
     if not fail: 
      print(new_room) 
      crave_room(new_room) # WIP 
      new_center = new_room.center 
      # rooms.append(new_room) 
      if len(rooms) != 0: 
       prev_center = rooms[len(rooms) - 1].center 

       if(randint(0, 1) == 1): 
        h_corridor(prev_center[0], new_center[0], prev_center[1]) 
        v_corridor(prev_center[1], new_center[1], prev_center[0]) 
       else: 
        v_corridor(prev_center[1], new_center[1], prev_center[0]) 
        h_corridor(prev_center[0], new_center[0], prev_center[1]) 
     if not fail: 
      rooms.append(new_room) 
    for room in rooms: 
     print(room) 


def h_corridor(x1, x2, y): 
    for x in xrange(min(x1, x2), max(x1, x2) + 1): 
     dungeon_map[x][y] = 1 


def v_corridor(y1, y2, x): 
    for y in xrange(min(y1, y2), max(y1, y2) + 1): 
     dungeon_map[x][y] = 1 

place_rooms() 

但每当我运行它，我得到以下错误：

Traceback (most recent call last): 
    File "/home/user/dungeon.py", line 114, in <module> 
    place_rooms() 
    File "/home/user/dungeon.py", line 87, in place_rooms 
    crave_room(new_room) 
    File "/home/user/dungeon.py", line 65, in crave_room 
    dungeon_map[x][y] = 1 
IndexError: list index out of range 

对于我从我的代码了解，crave_room功能应能正常工作，因为我使用的是min和max函数。并且由于h_corridor和v_corridor函数以类似的方式工作它们呈现相同类型的问题。

我不确定是否因为使用矩阵作为原始文章中使用的画布的替代物而发生问题。我怀疑本地/全球变量问题，但我不认为这是问题所在。恐怕我犯了一个非常愚蠢的错误，没有看到它。

任何有关更好的数据结构使用的代码改进技巧或建议都是值得欢迎的，如果有人有这个问题，最好在Python上更清晰/更简单的文章，我在这里看到很多相关的帖子，但我仍然有点失落。

感谢您的任何帮助。 ：d

Answer 1

你有你的dungeon_map正确声明：

dungeon_map = [[None] * MAP_WIDTH] * MAP_HEIGHT 

正确的方法应该是：

dungeon_map = [[None] * MAP_HEIGHT] * MAP_WIDTH 

现在你做到这一点，让我们来看看第二，更严重的问题。让我们在更小的规模（小图）的实验：

MAP_WIDTH = 4 
MAP_HEIGHT = 2 
dungeon_map = [[None] * MAP_HEIGHT] * MAP_WIDTH 

print('\nBefore Assignment:') 
print(dungeon_map) 

dungeon_map[2][1] = 'y' 

print('\nAfter Assignment:') 
print(dungeon_map) 

在这个实验中，我们创建了一个4列×2行矩阵，我们改变一个单元格的值，所以让我们来看看输出：

Before Assignment: 
[[None, None], [None, None], [None, None], [None, None]] 

After Assignment: 
[[None, 'y'], [None, 'y'], [None, 'y'], [None, 'y']] 

这是怎么回事？基本上，你声明相同的清单，MAP_WIDTH次。下面的报关行是方便和聪明，但不正确的：

dungeon_map = [[None] * MAP_HEIGHT] * MAP_WIDTH 

正确的方法来声明这样一个矩阵是：

dungeon_map = [[None for x in range(MAP_HEIGHT)] for y in range(MAP_WIDTH)]