我想实现名为MyClass的类。这个类应该是一个singleton,并且它必须从BaseClass继承。
最后,我想出了以下解决方案:
import random
class Singleton(object):
_instances = {}
def __new__(cls, *args, **kwargs):
if cls not in cls._instances:
cls._instances[cls] = super(Singleton, cls).__new__(cls, *args, **kwargs)
return cls._instances[cls]
class BaseClass(object):
def __init__(self, data):
self.value = random.random()
self.data = data
def asfaa(self):
pass
class MyClass(BaseClass, Singleton):
def __init__(self, data=3):
super().__init__(data)
self.a = random.random()
inst = MyClass(3)
如果MyClass的def __init__(self, data=3)
没有任何参数,则Evrythig工作正常
否则我会得到错误
line 9, in __new__
cls._instances[cls] = super(Singleton, cls).__new__(cls, *args, **kwargs)
TypeError: object.__new__() takes exactly one argument (the type to instantiate)
如何向MyClass提供任何参数?
所以,您的错误是TypeError: object.__new__() takes exactly one argument (the type to instantiate)
。如果您查看您的代码,您正在执行super(Singleton, cls).__new__(cls, *args, **kwargs)
。super(Singleton, cls)
引用object
类,因为您的Singleton
类继承了object
。你只需要改变这个:
cls._instances[cls] = super(Singleton, cls).__new__(cls, *args, **kwargs)
到此:
cls._instances[cls] = super(Singleton, cls).__new__(cls)
因为CCD_ 10不接受任何额外的参数。