如何在 Python 中创建没有 getter 的二传手?

Question

class My_Class:
def __init__(self):
self._x = 0
@property
def x(self):
return self._x
@x.setter
def x(self, x):
self._x = x

如果我从上面的代码中删除以下 getter：

@property
def x(self):
return self._x

代码停止工作。如何在没有吸气剂的情况下创建二传手？

Answer 1

property函数不必用作装饰器：装饰器可以用作函数：

class My_Class:
def _set_x(self, value):
self._x = value
x = property(fset=_set_x)  # now value has only a setter
del _set_x  # optional: delete the unneeded setter function
instance = My_Class()
instance.x= 8  # the setter works
print(instance._x) # the "private" value
print(instance.x) # raises: AttributeError: unreadable attribute

Answer 2

class My_Class:
def __init__(self):
self._x = 0
@property
def x(self):
raise RuntimeError('This property has no getter!')
@x.setter
def x(self, x):
self._x = x

Answer 3

这是我已经提供的另一种答案：制作你自己的只写描述符。

class WriteOnly:
def __init__(self, private_name):
self.private_name = private_name
def __set__(self, obj, value):
obj.__dict__[self.private_name] = value
def __get__(self, obj, type=None):
raise AttributeError('unreadable attribute')

class My_Class:
x = WriteOnly('_x')
instance = My_Class()
instance.x = 8  # the setter works
print(instance._x) # the "private" value
print(instance.x) # raises: AttributeError: unreadable attribute