我正在嘗試開發一種機制來檢測對繼承具有魯棒性的無效 kwarg。我想創建一個帶有檢查意外 kwarg 的 init 方法的類，并且我想創建另一個類，該類繼承自具有相同 kwarg 檢查的第一個類。這可能比兩層更深，但我認為解決兩層可以進一步推斷。這是我的嘗試：
class MyClass(object):
def __init__(self, **kwargs):
# possible kwargs and default values
self._kwargs_def = {
'a':1,
'b':2,
'c':3,
}
self.a = kwargs.pop('a', self._kwargs_def['a'])
self.b = kwargs.pop('b', self._kwargs_def['b'])
self.c = kwargs.pop('c', self._kwargs_def['c'])
assert len(kwargs) == 0, f"Invalid kwargs: {kwargs.keys()}"
class MyChildClass(MyClass):
def __init__(self, **kwargs):
super.__init__() # run once to generate _kwargs_def
# repeat to override defaults with any appropriate kwargs
super.__init__(**{key:val for key, val in kwargs.items() if key in super._kwargs_def})
self._kwargs_def.update({'d':4, 'e':5})
self.d = kwargs.pop('d', self._kwargs_def['d'])
self.e = kwargs.pop('e', self._kwargs_def['e'])
assert len(kwargs) == 0, f"Invalid kwargs: {kwargs.keys()}"
my_instance = MyClass(a=7) # works
# I need a way around this: TypeError: descriptor '__init__' of 'super' object needs an argument
my_child_instance = MyChildClass(e=37) # doesn't work but should???
my_instance = MyClass(z=7) # fails and should fail
my_child_instance = MyChildClass(z=37) # fails but for wrong reason
uj5u.com熱心網友回復：
你讓這件事變得比它需要的更難。請注意，我在派生類中根本沒有代碼。
class MyClass(object):
kwargs_def = {
'a':1,
'b':2,
'c':3,
}
def __init__(self, **kwargs):
# possible kwargs and default values
assert all(k in self.kwargs_def for k in kwargs), f"Invalid kwargs: {kwargs.keys()}"
self.__dict__.update( self.kwargs_def )
self.__dict__.update( kwargs )
class MyChildClass(MyClass):
kwargs_def = MyClass.kwargs_def.copy()
kwargs_def.update({
'd':4,
'e':5
})
my_instance = MyClass(a=7) # works
my_child_instance = MyChildClass(e=37) # doesn't work but should???
my_instance = MyClass(z=7) # fails and should fail
my_child_instance = MyChildClass(z=37) # fails but for wrong reason
uj5u.com熱心網友回復：
Python 已經檢查了無效的關鍵字引數。只需使用內置機制：
class MyClass:
def __init__(self, *, a=1, b=2, c=3):
self.a = a
self.b = b
self.c = c
class MyChildClass(MyClass):
def __init__(self, *, d=4, e=5, **kwargs):
super().__init__(**kwargs)
self.d = d
self.e = e
任何無效的關鍵字引數都將被 拒絕MyClass.__init__。（位置引數將被拒絕，因為這些引數被定義為僅關鍵字。）
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