类型错误：缺少一个必需的位置参数

Question

我正在做一个游戏作为一个有趣的副项目，我遇到了这个错误，我真的不知道为什么会发生。。。

代码如下：

class players:
    def __init__(self, location, image_file, direction):
        self.location = location
        self.image_file = image_file
        self.direction = direction
        self.rect = self.image_file.get_rect()

    def turn(self, direction, playerImages):
        keys = pygame.key.get_pressed()
        if keys[pygame.K_a] == True:
            self.direction -= 1
            if self.direction < -3:
                self.direction = 3
        if keys[pygame.K_d] == True:
            self.direction = 1
            if self.direction > 3:
                self.direction = 3

        if self.direction == -3:
            self.image_file = playerImages[0]
        if self.direction == -2:
            self.image_file = playerImages[1]
        if self.direction == -1:
            self.image_file = playerImages[2]
        if self.direction == 0:
            self.image_file = playerImages[3]
        if self.direction == 1:
            self.image_file = playerImages[4]
        if self.direction == 2:
            self.image_file = playerImages[5]
        if self.direction == 3:
            self.image_file = playerImages[6]

        return self.direction, self.image_file

我称之为：

skierDirection, playerImage = players.turn(skierDirection, playerImages)

我得到的错误是：

Traceback (most recent call last):
  File "C:\Users\Owen\Desktop\coding compile file\SkiFreeX\SkiFreeX.py", line 129, in <module>
    main()
  File "C:\Users\Owen\Desktop\coding compile file\SkiFreeX\SkiFreeX.py", line 122, in main
    skierDirection, playerImage = players.turn(skierDirection, playerImages)
TypeError: turn() missing 1 required positional argument: 'playerImages'
[Finished in 0.385s]

有什么想法吗？

Answer 1

不应直接调用类方法，而应创建该类的实例：

p1 = players(your, values, here)
skierDirection, playerImage = p1.turn(skierDirection, playerImages)

要详细说明您遇到的错误：

TypeError: turn() missing 1 required positional argument: 'playerImages'

这是因为turn需要一个players实例作为第一个参数（self）。类方法总是作为第一个参数传递给实例，因此p1.turn(skierDirection, playerImages)实际上会向players.turn传递3个参数。

Answer 2

您必须将（）与类名一起使用

遵循以下代码

skierDirection, playerImage = players().turn(skierDirection, playerImages)