Python如何从包含列表的列表中选择项目

Question

我在生成地图时遇到问题。它使用几个包含向量列表的列表。还有一组墙列表（该列表代表由矢量指向的地方迷宫）。所以我有随机问题。当我从迷宫列表中选择随机项目时。程序会变得疯狂，并创造一些没有多大意义的东西。我试图手动选择每个迷宫，并完美运作。我试图找到解决这个问题的方法，但没有回答这种问题。在这个循环中从迷宫列表中随机选择一个项目是错误的。编辑：这里是可以运行以查看结果的程序。

import pygame, random, sys 

WIDTH= 640 
HEIGHT = 480 
WHITE = (255, 255, 255) 
BLUE = (50, 50, 255) 
clock = pygame.time.Clock() 
screen= pygame.display.set_mode((WIDTH, HEIGHT)) 
screen.fill(WHITE) 

wall_list = pygame.sprite.Group() 
all_sprite_list = pygame.sprite.Group() 





class Wall(pygame.sprite.Sprite): 
    def __init__(self, x, y, width, height): 
     super().__init__() 

     self.image = pygame.Surface([width, height]) 
     self.image.fill(BLUE) 
     self.rect = self.image.get_rect() 
     self.rect.y = y 
     self.rect.x = x 





def ran_map(): 
    walls_1 = [ [0, 0, 40, 20], 
       [60, 0, 30, 20], 
       [0, 40, 40, 10], 
       [60, 40, 30, 10] 
       ] 
    walls_2 = [ [0, 0, 60, 10], 
       [40, 10, 20, 10], 
       [0, 30, 20, 20], 
       [20, 40, 70, 10], 
       [80, 0, 10, 40] 
       ] 
    walls_3 = [ [0, 0, 10, 50], 
       [10, 0, 80, 10], 
       [80, 10, 10, 40], 
       [30, 30, 30, 20] 
       ] 
s_maze = [walls_1, walls_2, walls_3] 

vectors = [[60, 60], [170, 60], [380, 60], [490, 60], [60, 370], [170, 370], [380, 370], [490, 370]] 

for item in vectors: 
    v1 = item[0] 
    v2 = item[1] 
    random_item = random.choice(s_maze) 
    for item in random_item: 
     w1 = item[0] 
     w2 = item[1] 
     s1 = w1+ v1 
     s2 = w2+ v2 
     wall = Wall(s1, s2, item[2], item[3]) 
     wall_list.add(wall) 
     all_sprite_list.add(wall) 



def xz(): 
    done = False 
    while not done: 
     pygame.init() 
     clock.tick(45) 
     ran_map() 
     all_sprite_list.draw(screen) 
     pygame.display.flip() 
     for event in pygame.event.get(): 
      if event.type == pygame.QUIT: 
       done = True 
    pygame.quit() 

def main(): 
    xz() 

main() 

Answer 1

的“要疯了”是最有可能是由于这个重复迭代变量：

for *item* in vectors: 
    ... 
    for *item* in random_item: 

我建议您简化代码的中间部分如下：

... 

mazes = { # a dictionary of mazes 
    'walls_1': [ [0, 0, 40, 20], 
       [60, 0, 30, 20], 
       [0, 40, 40, 10], 
       [60, 40, 30, 10] 
       ], 
    'walls_2': [ [0, 0, 60, 10], 
       [40, 10, 20, 10], 
       [0, 30, 20, 20], 
       [20, 40, 70, 10], 
       [80, 0, 10, 40] 
       ], 
    'walls_3': [ [0, 0, 10, 50], 
       [10, 0, 80, 10], 
       [80, 10, 10, 40], 
       [30, 30, 30, 20] 
       ] 
} 

vectors = [[60, 60], [170, 60], [380, 60], [490, 60], [60, 370], [170, 370], [380, 370], [490, 370]] 

for v1, v2 in vectors: 
    random_item = random.choice(list(mazes.values())) 

    for w1, w2, w3, w4 in random_item: 
     s1 = w1 + v1 
     s2 = w2 + v2 
     wall = Wall(s1, s2, w3, w4) 
     wall_list.add(wall) 
     all_sprite_list.add(wall) 

...