python - __init__ 中的类参数测试

Question

我有一个 Point 类，它接受位置、值和标志作为参数。这个类应该只接受整数作为位置和值参数。我尝试了下面的代码，但它不能正常工作。

class PointException(Exception):
    pass

class Point():
    def __init__(self, position, value, flag=False):
        try:
            if all([isinstance(x, int) for x in position, value]):
                self.position = position
                self.value = value
                self.point = (position, value)
            self.flag = flag
        except:
            raise PointException("Foo value and position must be integers.")

    def __repr__(self):
        return "< {0}, {1}, {2} >".format(self.position, self.value, self.flag)

    def __eq__(self, other):
        if not isinstance(other, Point):
            return False
        try:
            return all([self.point == other.point, self.flag == other.flag])
        except AttributeError:
            return False

    def __ne__(self, other):
        return not self.__eq__(other)

更新

例如，当我尝试 Point(1, 1.2) 时，我得到一个 AttributError。

AttributeError: Point instance has no attribute 'position'

Answer 1

if all([isinstance(x, int) for x in position, value])

应该是

if all(isinstance(x, int) for x in (position, value))

更一般地说，你必须在 __init__ 中引发异常，而不是用 except 捕获它:

def __init__(self, position, value, flag=False):
    if not all(isinstance(x, int) for x in (position, value)):
        raise PointException("Foo value and position must be integers.")

    self.position = position
    self.value = value
    self.point = (position, value)
    self.flag = flag

您可以在其他答案中了解其他方面的改进