python设计模式(策略模式)

#学习版本3.5.2#策略模式，定义一些列算法，把每一个算法都封装起来，并且使它们可以相互替换。#该模式使得算法可独立于使用它的客户变化#例如：出去旅游选择交通方式class TravelStrategy(object):    def travelAlgorithm(self):        passclass AirPlaneStrategy(TravelStrategy):    def travelAlgorithm(self):        print("travel by airplane")class TrainStrategy(TravelStrategy):    def travelAlgorithm(self):        print("travel by train")class BicycleStrategy(TravelStrategy):    def travelAlgorithm(self):        print("travel by bycycle")class PersonContext(object):    def __init__(self, strategy):        self._strategy = strategy    def changeStrategy(self, strategy):        self._strategy = strategy    def travel(self):        self._strategy.travelAlgorithm()if __name__ == "__main__":    pc = PersonContext(BicycleStrategy())    pc.travel()    pc.changeStrategy(TrainStrategy())    pc.travel()

运行结果

travel by bycycletravel by train