Python使用random类触发randrange空范围ValueError错误求助

• 初始房间被重置清空：generateLevel函数执行时先调用resetLevel把rooms数组全部设为0，你在全局预先设置的中心位置初始房间（值为1）直接被清空，findPossibleRooms遍历的时候找不到任何已存在的房间，候选列表始终为空。
• 全局变量未正确声明：possibleNextRoom是全局变量，在resetLevel、findPossibleRooms函数中修改时没有加global关键字，函数内操作的是局部同名变量，全局的候选列表永远是空，调用random.randrange(0, 0)直接触发报错。
• 候选列表重复追加：findPossibleRooms每次调用前没有清空旧数据，会反复追加重复坐标，导致后续生成逻辑异常。
• 数组索引越界风险：遍历房间时没有做边界校验，比如r=0时访问r-1会得到负索引，触发数组访问异常。

import random
import numpy as np

class Room:
  def __init__(self, name, contents):
    self.name = name
    self.contents = contents

rooms = np.zeros((11, 11))
maxRooms = 7
possibleNextRoom = []

def resetLevel():
  global rooms, possibleNextRoom
  # 清空所有房间
  for r in range(len(rooms)):
    for c in range(len(rooms[0])):
      rooms[r][c] = 0
  # 初始化中心起始房间
  halfHeight = int(len(rooms[1]) / 2)
  halfWidth = int(len(rooms[0]) / 2)
  rooms[halfWidth][halfHeight] = 1
  # 清空候选房间列表
  possibleNextRoom = []

def countRooms():
  global rooms
  roomCount = 0
  for r in range(len(rooms)):
    for c in range(len(rooms[0])):
      if rooms[r][c] == 1:
        roomCount += 1
  return roomCount

def findPossibleRooms():
  global possibleNextRoom, rooms
  # 每次重新查找前清空旧候选
  possibleNextRoom.clear()
  max_row = len(rooms) - 1
  max_col = len(rooms[0]) - 1
  for r in range(len(rooms)):
    for c in range(len(rooms[0])):
      if rooms[r][c] == 1:
        # 四个方向增加边界校验，避免越界
        if c + 1 <= max_col and rooms[r][c+1] != 1:
          possibleNextRoom.append((r, c+1))
        if c - 1 >= 0 and rooms[r][c-1] != 1:
          possibleNextRoom.append((r, c-1))
        if r - 1 >= 0 and rooms[r-1][c] != 1:
          possibleNextRoom.append((r-1, c))
        if r + 1 <= max_row and rooms[r+1][c] != 1:
          possibleNextRoom.append((r+1, c))

def addRoom():
  global possibleNextRoom, rooms
  # 无可用候选时直接返回避免报错
  if not possibleNextRoom:
    return
  nextRoom = random.randrange(0, len(possibleNextRoom))
  rooms[possibleNextRoom[nextRoom][0]][possibleNextRoom[nextRoom][1]] = 1
  possibleNextRoom.pop(nextRoom)

def generateLevel():
  resetLevel()
  while countRooms() < maxRooms:
    findPossibleRooms()
    addRoom()

def displayLevel():
  print(rooms)

generateLevel()
displayLevel()

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