方法没有从__new__内部被调用

Question

在下面的代码中，我试图理解init新和． 我遇到的问题是方法callBeforeInit()从未被调用。

请告诉我为什么它没有被调用，以及如何调用它。

:

class varargs:
def __new__(cls):
print("in object creation")
callBeforeInit()
return super(varargs, cls).__new__(cls)
#return object.__new__(cls)
def __init__(self):
print("in object indtansiation")
def callBeforeInit():
print("called before init")
v = varargs()

误差:

in object creation
Traceback (most recent call last):
File "d:python workspaceVarargs.py", line 15, in <module>
v = varargs()
File "d:python workspaceVarargs.py", line 5, in __new__
callBeforeInit()
NameError: name 'callBeforeInit' is not defined

Answer 1

new在创建对象之前调用，因此此时不存在这样的方法。

应该是

class varargs:
def __new__(cls):
print("in object creation")
cls.callBeforeInit()
return super(varargs, cls).__new__(cls)
#return object.__new__(cls)
def __init__(self):
print("in object indtansiation")
@classmethod
def callBeforeInit(cls):
print("called before init")
v = varargs()