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- 2016-5-10
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- class Vehicle:
- def __init__(self, speed):
- self.speed = speed
- def drive(self, distance):
- print 'need %f hour(s)' % (distance / self.speed)
- class Bike(Vehicle):
- pass
- class Car(Vehicle):
- def __init__(self, speed, fuel):
- Vehicle.__init__(self, speed)
- self.fuel = fuel
- def drive(self, distance):
- Vehicle.drive(self, distance)
- print 'need %f fuels' % (distance * self.fuel)
- b = Bike(15.0)
- c = Car(80.0, 0.012)
- b.drive(100.0)
- c.drive(100.0)
- d=Car(80,None)
- d.Vehicle.drive(100)
- #下面是报错
- '''
- need 6.666667 hour(s)
- need 1.250000 hour(s)
- need 1.200000 fuels
- Traceback (most recent call last):
- File "123.py", line 26, in <module>
- d.Vehicle.drive(100)
- AttributeError: Car instance has no attribute 'Vehicle'
- '''
复制代码 在crossin老师代码的最后添加了两行,想尝试一下子类调用父类里的函数,然而运行的时候报错了,这个错误为什么呀 |
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