我正在寻找 property 内置函数的纯 Python 实现,以了解初始化的工作原理。我发现许多处理描述符接口(interface)(__get__、__set__)但没有描述setter 或deleter方法。这是definition吗在Python Decorator Library (大致)它的实现方式?
请您参考如下方法:
属性是一个简单、直接的描述符。描述符协议(protocol)由三个方法组成:__get__、__set__和__delete__。每个操作的属性仅调用用户提供的函数。
class my_property(object):
def __init__(self, getter, setter, deleter):
self.getter = getter
self.setter = setter
self.deleter = deleter
def __get__(self, instance, owner):
return self.getter(instance)
def __set__(self, instance, value):
self.setter(instance, value)
def __delete__(self, instance):
self.deleter(instance)
class Foo(object):
def __init__(self):
self._x = 42
def get_x(self):
print 'getter'
return self._x
def set_x(self, value):
print 'setter'
self._x = value
def del_x(self):
print 'deleter'
del self._x
x = my_property(get_x, set_x, del_x)
obj = Foo()
print obj.x
obj.x = 69
del obj.x
print obj.x
