用于任务管道的 Python 模式

Question

我正在尝试在汽车对象上创建一个简单的管道

打造汽车车轮

给汽车加刹车

存车

我为此任务开发的代码是:

def build_brakes(car) :
    car.brakes = 'new high quality brakes'
    return car
        
class Car :
    def __init__(self , wheels):
        self.wheels = wheels
        self.jsonTransform = {}
        self.jsonTransform['wheels'] = wheels
        
    def toJson(self):
        return self.jsonTransform

def store(car):
    return 'car' , car , 'stored'
    
c = Car("wheels")
print(c.toJson())

car_with_brakes = build_brakes(c)
print(car_with_brakes.toJson())

stored = store(c)
print(stored)

哪个打印:

{'wheels': 'wheels'}
{'wheels': 'wheels'}
('car', <__main__.Car object at 0x7f40a86bdcf8>, 'stored')

线路 print(car_with_brakes.toJson())版画 {'wheels': 'wheels'} .有没有我可以使用的模式来为汽车和 brakes 生成 JSON属性并封装上面描述的管道？我可以创建一个名为 CarWithBrakes 的新类如 :

class CarWithBrakes(Car):
    
    def __init__(self , car, brakes):
        self.car = car
        self.brakes = brakes

    def toJson(self):
        self.jsonTransform = {}
        self.jsonTransform['wheels'] = self.car.wheels
        self.jsonTransform['brakes'] = self.car.brakes
        return self.jsonTransform
    
car_with_brakes = CarWithBrakes(c , 'new high qualiy brakes')

car_with_brakes.toJson()

打印:

{'wheels': 'wheels', 'brakes': 'new high qualiy brakes'}

但这对于一个看似简单的问题来说似乎太过分了？

Answer 1

您有多种选择。
一是调整build_brakes功能:

# note brakes x breaks
def build_brakes(car) :
    car.brakes = 'new high quality brakes'
    car.jsonTransform['breaks'] = car.brakes
    return car

另一个(IMO 更清洁)是修改 toJson方法:

# note brakes x breaks
class Car :
    def __init__(self , wheels):
        self.wheels = wheels
    def toJson(self):
        ret = {'wheels':self.wheels}
        if hasattr(self,"brakes"):
            ret['breaks'] = self.brakes
        return ret