Python:从多个父类继承时出现问题
Python:从多个父类继承时出现问题
提问于 2018-07-13 04:54:45
我有一个子类，它需要从两个父类继承，只是方法和单个属性不同。当实例化这个类时，我得到一个错误，声明我正在使用许多参数。当删除一个参数时，它会显示我使用的不够多。
球
class Ball:
"""
base class for bouncing objects
"""
def __init__(self, bounds, position, velocity, color, radius):
self.position = position
self.velocity = velocity
self.bounds = bounds
self.color = color
self.radius = radius
def update(self):
# bounce at edges. TODO: Fix sticky edges
if self.position.x < 0 + self.radius or self.position.x > self.bounds[0] - self.radius: # screen width
self.velocity.x *= -1
if self.position.y < 0 + self.radius or self.position.y > self.bounds[1] - self.radius: # screen height
self.velocity.y *= -1
self.position += self.velocity
def draw(self, screen, pygame):
# cast x and y to int for drawing
pygame.draw.circle(screen, self.color, [int(self.position.x), int(self.position.y)], self.radius)BouncingBall
class BouncingBall(Ball):
"""
ball effected by gravity
"""
def __init__(self, bounds, position, velocity, color, radius, weight):
super().__init__(bounds, position, velocity, color, radius)
self.weight = weight
def update(self):KineticBall
class KineticBall(Ball):
"""
A ball that collides with other collidable balls using simple elastic circle collision
"""
def __init__(self, bounds, position, velocity, color, radius, object_list):
super().__init__(bounds, position, velocity, color, radius)
self.object_list = object_listKineticBouncing
class KineticBouncing(BouncingBall, KineticBall):
def __init__(self, bounds, position, velocity, color, radius, weight, object_list):
super().__init__(bounds, position, velocity, color, radius, weight, object_list)ball => KineticBouncing
# super().__init__(bounds, position, velocity, color, radius, weight, object_list)
TypeError: __init__() takes 7 positional arguments but 8 were given
ball = KineticBouncing(SCREEN_SIZE, Vector2(50, 50), Vector2(3, 3), [255, 0, 255], 10, -1, object_list)让我们试试别的..。
所以这很让人困惑..相反，我找到了Python3 Multiple Inheritance，我相信它会解决我的问题。只需使用父级名称+初始化，而不是super()，对吗？
KineticBouncing
class KineticBouncing(BouncingBall, KineticBall):
def __init__(self, bounds, position, velocity, color, radius, weight, object_list):
BouncingBall.__init__(self, bounds, position, velocity, color, radius, weight)
KineticBall.__init__(self, bounds, position, velocity, color, radius, object_list)ball => KinetBouncing
#Traceback (most recent call last):
# File "draw.py", line 99, in <module>
# main()
# File "draw.py", line 61, in main
# debug_create_balls(object_list)
# File "draw.py", line 43, in debug_create_balls
# ball = KineticBouncing(SCREEN_SIZE, Vector2(50, 50), Vector2(3, 3), [255, 0, 255], 10, -1, object_list)
# File "/home/adam/Desktop/web_dev/lambda_school/python/Python-OOP-Toy/src/ball.py", line 115, in __init__
# BouncingBall.__init__(self, bounds, position, velocity, color, radius, weight)
# File "/home/adam/Desktop/web_dev/lambda_school/python/Python-OOP-Toy/src/ball.py", line 33, in __init__
# super().__init__(bounds, position, velocity, color, radius)
#TypeError: __init__() missing 1 required positional argument: 'object_list'
ball = KineticBouncing(SCREEN_SIZE, Vector2(50, 50), Vector2(3, 3), [255, 0, 255], 10, -1, object_list)那么，我到底应该如何从这两个父类继承呢？
回答 2
Stack Overflow用户
发布于 2018-07-13 05:25:14
正如其他人所指出的，你应该重新设计你的类的使用。直接的问题是，super()解析为有问题的对象的第一个父类(self)，而不是您当时所在的__init__方法的父类。
当您尝试初始化KineticBouncing对象时，将调用KineticBouncing.super().__init__()。它显式地调用它的两个父类的__init__方法。当它第一次调用BouncingBall中的语句时，第一个活动语句是
super().__init__(bounds, position, velocity, color, radius)我相信您期望这会调用Ball.__init__；这不是super的工作方式。相反，它基于对象解析super，该对象属于KineticBouncing类。所以..。对KineticBouncing来说，super是什么？请注意，在您编写的两个__init__调用之间，至少有一次是错误的。
我将留给您阅读评论中提供的链接。这些将帮助您从Python的继承结构角度进行思考。根据您发布的内容，我认为您在处理切换时会遇到一些问题；您只是从其他地方选择了一个层次结构模型。
Stack Overflow用户
发布于 2018-07-13 05:58:06
在你父母的所有初始化中使用*args
class Ball(object):
def __init__(self, *args):
print ('IN Ball')
class BouncingBall(Ball):
"""
ball effected by gravity
"""
def __init__(self, bounds, position, velocity, color, radius, weight, *args):
print ('IN BouncingBall')
super().__init__(bounds, position, velocity, color, radius, *args)
self.weight = weight
class KineticBall(Ball):
"""
A ball that collides with other collidable balls using simple elastic circle collision
"""
def __init__(self, bounds, position, velocity, color, radius, object_list, *args):
print ('IN KineticBall')
super().__init__(bounds, position, velocity, color, radius, *args)
self.object_list = object_list
class KineticBouncing(BouncingBall, KineticBall):
def __init__(self, bounds, position, velocity, color, radius, weight, object_list):
print ('IN KineticBouncing')
super().__init__(bounds, position, velocity, color, radius, weight, object_list)现在开始创建一个新的动态弹跳球
ball = KineticBouncing('SCREEN_SIZE', 'Vector2(50, 50)', 'Vector2(3, 3)', [255, 0, 255], 10, -1, 'object_list')
IN KineticBouncing
IN BouncingBall
IN KineticBall
IN Ball页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/51314305
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