Question

我有这段代码：

import pygame
import block as b
import constants as c
import copy
def walls():
    walls_list = []

    wall_proto = b.Wall(c.WHITE, 40, 40, 20, 80)
    wall = copy.copy(wall_proto)
    wall.rect_x = 50
    print wall_proto.rect_x
    print wall.rect_x

walls()

打印：

50
50

但我想打印它

40
50

我想在游戏中创建各种“墙”。那些墙可能有很多类似的数据，但也有一些不同。所以我想要一些可用于复制的墙对象，然后在不同的墙上设置不同的属性。如果我使用简单副本，那么如果我更改复制对象中的任何内容，则所有其他对象也将更改该值。我可以使用deepcopy，但它很慢。是否有解决方案/更好的解决方案而不是深度复制？

更新

按照墙要求：

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

        self.image = pygame.Surface([width, height])
        self.image.fill(color)

        self.rect = self.image.get_rect()
        self.rect.x = x
        self.rect.y = y
        #to get/set values
        self._width = width
        self._height = height

    @property
    def rect_x(self):
        return self.rect.x
    @property
    def rect_y(self):
        return self.rect.y
    @property
    def width(self):
        return self._width
    @property
    def height(self):
        return self._height

    @rect_x.setter
    def rect_x(self, value):
        self.rect.x = value

    @rect_y.setter
    def rect_x(self, value):
        self.rect.y = value

    @width.setter
    def width(self, value):
        self._width = value

    @height.setter
    def height(self, value):
        self._height = value

Answer 1

如果它是一个简单的列表（没有任何可变对象），你可以使用：List [：]或Dict.copy（）

Answer 2

我会这样做：

将所有参数更改为关键字参数
向Wall构造函数添加wall=关键字arg。

如果设置了wall，请将值复制到新实例中，然后根据其他参数进行设置。像这样：

class Wall(pygame.sprite.Sprite):
    def __init__(self, color=None, x=None, y=None, width=None, height=None, wall=None):
        pygame.sprite.Sprite.__init__(self)
        # check parameters are valid
        assert any([color and x and y and width, wall]), "invalid arguments"
        # assign parameters from given wall or parameters
        x      = x or wall.rect_x
        y      = y or wall.rect_y
        color  = color or wall.color
        height = height or wall.height
        width  = width or wall.width
        ...

然后你可以编写如下代码：

wall1 = Wall(c.WHITE, 40, 40, 20, 80)
wall2 = Wall(color=c.BLUE, wall=wall1)

Answer 3

最终，这并不是你应该如何做到这一点。相反，请考虑制作一个classmethod，它将同时定义整个范围的墙壁。有点像...

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

        self.image = pygame.Surface([width, height])
        self.image.fill(color)

        self.rect = self.image.get_rect()
        self.rect.x = x
        self.rect.y = y
        # since your properties are only getters and setters, don't use them
        self.width = width
        self.height = height

    @classmethod
    def make_walls(cls, color, coords):
        """Makes a grouping of walls of a specified color, given
        a list of (x, y, width, height) tuples"""
        list_of_walls = []
        for details in coords:
            x, y, width, height = details
            wall = cls(color, x, y, width, height)
            list_of_walls.append(wall)
        return list_of_walls
        # or MUCH less clear:
        # return [cls(color, *details) for details in coords)]

然后你可以做任何你喜欢的墙：

wall_locations = [
    (1, 1, 1, 1),
    (1, 2, 1, 1),
    (1, 3, 1, 1),
    (1, 4, 1, 1),
    ... ]
new_walls = b.Wall.make_walls(c.WHITE, wall_locations)

Python - 如何在不使用deepcopy的情况下复制对象（因此它不会引用旧对象）？

3 个答案: