浅谈Python的property装饰器

Python的property装饰器

property装饰器可以装饰类的方法从而可以用属性访问来触发该方法，同时该方法带有getter和setter装饰器。

举例：

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class Resistor(object):
    def __init__(self, ohms):
        self.ohms = ohms
        self.voltage = 0
        self.current = 0

class VoltageResistance(Resistor):
    def __init__(self, ohms):
        super().__init__(ohms)
        self._valtage = 0

    @property
    def voltage(self):
        return self._valtage

    @voltage.setter
    def voltage(self, voltage):
        self._voltage = voltage
        self.current = self._voltage / self.ohms

class BoundedResistance(Resistor):
    def __init__(self, ohms):
        super().__init__(ohms)

    @property
    def ohms(self):
        return self._ohms

    @ohms.setter
    def ohms(self, ohms):
        if ohms <= 0: # 控制属性的值范围或限制属性的修改
            raise ValueError("%f ohms must be > 0" % ohms)
        self._ohms = ohms

class FixedResistance(Resistor):
    @property
    def ohms(self):
        return self._ohms

    @ohms.setter
    def ohms(self, ohms):
        if hasattr(self, '_ohms'):
            raise AttributeError("Can't set attribute")
        self._ohms = ohms

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