Question

我的LabelledPoint类继承自Point类。我希望此类具有x和y坐标以及将是字符串的label属性。

import numbers
def clamp(v,_min,_max):
    return max(min(v,_max),_min)

class Point:
    def __init__(self,x,y):
        self.x = clamp(x,0,10)
        self.y = clamp(y,0,10)

    def __str__(self):
        return(str((self.x,self.y)))
    @property
    def _add_(self,p):
        a=self.x + p.x
        b=self.y + p.y
        return Point(a,b)

    @property
    def x(self):
        return self.__x
    @x.setter
    def x(self, value):
        if not isinstance(value, numbers.Number):
            raise AttributeError()
        self.__x = clamp(int(value), 0, 10)

    @property
    def y(self):
        return self.__y

    @y.setter
    def y(self, value):
        if not isinstance(value, numbers.Number):
            raise AttributeError()
        self.__y = clamp(int(value), 0, 10)

class LabelledPoint(Point):

        def __init__(self,x,y,label):
            Point.__init__(self,x,y)
            label=str()
            self.label=label

        def __str__(self):
            return (str((self.label)))

        def _get_label(self):
            return self._label

        def _set_label(self,label):
            raise AttributeError()
            label=property(_get_label,_set_label)
            return label

我想获得此输入：

lp = LabelledPoint(5,15, "foo")
print (lp) # output "(5,10) : foo"

我仅获得输出：

(5,10)

我不知道我的错误在哪里谢谢

Answer 1

_str_

您的Point.__str__(self)方法周围只有一个下划线。它也不会对值dd$time = Map(f = seq, dd$start, dd$end) tidyr::unnest(dd[c("val", "time")]) # val time # 1 a 2 # 2 a 3 # 3 a 4 # 4 b 2 # 5 b 3 # 6 b 4 # 7 b 5 # 8 c 1 # 9 c 2 # 10 c 3
做任何事情

@帕特里克·豪（Patrick Haugh）

（我自己不能说更好）

Answer 2

您在代码中遇到了很多不幸（请参阅注释）：

import numbers


def clamp(v, _min, _max):
    return max(min(v, _max), _min)


class Point:
    def __init__(self, x, y):
        self._x = clamp(x, 0, 10)    # changed from no underscore to single underscore 
        self._y = clamp(y, 0, 10)

    def __str__(self):               # added explicit return of the class name
        return f"{self.__class__.__name__}{str((self._x, self._y))}"

    def __add__(self, p):            # changed from double underscore to single underscore, and removed the @property
        a = self._x + p._x
        b = self._y + p._y
        return self.__class__(a, b)  # use super() i/o explicit class

    @property
    def x(self):
        return self._x

    @x.setter
    def x(self, value):              # changed from double underscore to single underscore everywhere below this point
        if not isinstance(value, numbers.Number):
            raise AttributeError()
        self._x = clamp(int(value), 0, 10)

    @property
    def y(self):
        return self._y

    @y.setter
    def y(self, value):
        if not isinstance(value, numbers.Number):
            raise AttributeError()
        self._y = clamp(int(value), 0, 10)


class LabelledPoint(Point):

    def __init__(self, x, y, label):
        super().__init__(x, y)        # calling super() i/o explicit class
        self._label = str(label)      # assign label to attribute

    def __str__(self):                # call to super(), then concatenate the label value
        return f"{super().__str__()}: {str(self._label)}"

    def get_label(self):              # remove single underscore from getter and setter
        return self._label            # why not use @property like in the superclass?

    def set_label(self, label):       # remove raise exception that made th code unreachable
        self._label = label


if __name__ == '__main__':
    p = Point(2, 12)
    print(p)
    lp = LabelledPoint(5, 15, "foo")
    print(lp)

输出：

Point(2, 10)
LabelledPoint(5, 10): foo

属性类转换python

2 个答案:

输出：