我正在尝试迭代元组的数组(以常量形式):
SPRITE_RIGHT = [(0, 0), (16, 0), (32, 0)]
SPRITE_LEFT = [(0, 16), (16, 16), (32, 0)]
SPRITE_UP = [(0, 32), (16, 32), (32, 0)]
SPRITE_DOWN = [(0, 48), (16, 48), (32, 0)]
def symbol(self):
self._status += 1
if (self._status > 2):
self._status = 0
if (self._dx > 0):
(x, y) = PacMan.SPRITE_RIGHT[self._status]
return (x,y)
if (self._dx < 0):
(x, y) = PacMan.SPRITE_LEFT[self._status]
return (x,y)
if (self._dy > 0):
(x, y) = PacMan.SPRITE_DOWN[self._status]
return (x,y)
if (self._dy < 0):
(x, y) = PacMan.SPRITE_UP[self._status]
return (x,y)
...
for a in arena.actors():
if not isinstance(a, Wall):
x, y, w, h = a.rect()
xs, ys = a.symbol() #This line gives me the problem
screen.blit(sprites, (x, y), area=(xs, ys, w, h))
当我执行程序时,我收到此错误:
TypeError: 'NoneType' object is not iterable
对于每个演员,我调用方法symbol()来获取其图像
当我打印PacMan.SPRITE_UP [0]时,它返回正确的 元组
答案 0 :(得分:0)
检查a.symbol()
返回的值。看起来它试图将它解开为两个值并失败。
执行此操作时:
xs, ys = a.symbol() #This line gives me the problem
它调用a.symbol()
,它返回一个值。代码假设这一点
value是一个包含两个值的iterable。然后是xs
和ys
改为引用这两个值。
如果a.symbol()
返回的值不是这样的值
可迭代,分配将失败。你收到的错误信息,
TypeError: 'NoneType' object is not iterable
,建议
a.symbol()
正在返回None
。