python3中的property有一个很有意思的功能，它能将类中的方法像类属性一样调用！

class property(fget=None, fset=None, fdel=None, doc=None)

我们先来简单了解一下这个property类，下面看一下官网给出的例子：

class C:def __init__(self):self._x = Nonedef getx(self):return self._xdef setx(self, value):self._x = valuedef delx(self):del self._xx = property(getx, setx, delx, "I'm the 'x' property.")  # 这里的x相当于类属性c = C()  # 生成一个对象
c.x = 10  # 设置self._x=10，实际调用的就是类中setx方法
c.x  # 获取self._x的值，实际调用的就是类中getx方法
del c.x  # 删除self._x的值，实际调用的就是类中delx方法

是不是感觉很有意思，很不可思议！property中fget是一个函数，它获取属性值；fset是一个函数,它设置一个属性值；fdel是一个函数,它删除一个属性值；doc为该属性创建一个docstring。你只要在使用时在对应的形参位置放上你写的对应函数，就可以轻松使用了。

我们还可以将property作为装饰器来使用，还是使用官网的例子：

class C:def __init__(self):self._x = None@propertydef x(self):"""I'm the 'x' property."""return self._x@x.setterdef x(self, value):self._x = value@x.deleterdef x(self):del self._x

property对象有getter、setter、deleter三个方法，getter获取属性值，setter设置属性值，deleter设置属性值，这个例子的效果跟上一个例子的效果完全相同！我们看到里面的方法名是一模一样的，但是达到的效果却是不同的。第一个x方法是获取属性值，第二个x方法是设置属性值，第三个x方法是删除属性值。

你看到这里是不是以为这一切都是property帮你做到的，错，错，错！其实property只做了一件事件，它将你的方法能像类属性一样使用，至于里面的查、删、改，其实都是你自己写的函数实现的！fget、fset、fdel、setter、deleter这些仅仅只是名字而且，方便你识别，其他什么作用都没有！

我们来看一下property的源代码：

class property(object):"""property(fget=None, fset=None, fdel=None, doc=None) -> property attributefget is a function to be used for getting an attribute value, and likewisefset is a function for setting, and fdel a function for del'ing, anattribute.  Typical use is to define a managed attribute x:class C(object):def getx(self): return self._xdef setx(self, value): self._x = valuedef delx(self): del self._xx = property(getx, setx, delx, "I'm the 'x' property.")Decorators make defining new properties or modifying existing ones easy:class C(object):@propertydef x(self):"I am the 'x' property."return self._x@x.setterdef x(self, value):self._x = value@x.deleterdef x(self):del self._x"""def deleter(self, *args, **kwargs): # real signature unknown""" Descriptor to change the deleter on a property. """passdef getter(self, *args, **kwargs): # real signature unknown""" Descriptor to change the getter on a property. """passdef setter(self, *args, **kwargs): # real signature unknown""" Descriptor to change the setter on a property. """passdef __delete__(self, *args, **kwargs): # real signature unknown""" Delete an attribute of instance. """passdef __getattribute__(self, *args, **kwargs): # real signature unknown""" Return getattr(self, name). """passdef __get__(self, *args, **kwargs): # real signature unknown""" Return an attribute of instance, which is of type owner. """passdef __init__(self, fget=None, fset=None, fdel=None, doc=None): # known special case of property.__init__"""property(fget=None, fset=None, fdel=None, doc=None) -> property attributefget is a function to be used for getting an attribute value, and likewisefset is a function for setting, and fdel a function for del'ing, anattribute.  Typical use is to define a managed attribute x:class C(object):def getx(self): return self._xdef setx(self, value): self._x = valuedef delx(self): del self._xx = property(getx, setx, delx, "I'm the 'x' property.")Decorators make defining new properties or modifying existing ones easy:class C(object):@propertydef x(self):"I am the 'x' property."return self._x@x.setterdef x(self, value):self._x = value@x.deleterdef x(self):del self._x# (copied from class doc)"""pass@staticmethod # known case of __new__def __new__(*args, **kwargs): # real signature unknown""" Create and return a new object.  See help(type) for accurate signature. """passdef __set__(self, *args, **kwargs): # real signature unknown""" Set an attribute of instance to value. """passfdel = property(lambda self: object(), lambda self, v: None, lambda self: None)  # defaultfget = property(lambda self: object(), lambda self, v: None, lambda self: None)  # defaultfset = property(lambda self: object(), lambda self, v: None, lambda self: None)  # default__isabstractmethod__ = property(lambda self: object(), lambda self, v: None, lambda self: None)  # default

看到上面的源代码恍然大悟没，fdel、fget、fset都只是执行你函数里面的代码而已！所以我们就记住一句话就够了：“property能让你的方法像类属性一样使用”。