Website exercise

point.py

import operator


class Point:
    """A 3D, (x, y, z) mutable point

    >>> p1 = Point(1, 2, 3)
    >>> p1
    Point(x=1, y=2, z=3)
    >>> p2 = Point(1, 2, 3)
    >>> p1 == p2
    True
    >>> p2.x = 4
    >>> p1 == p2
    False
    >>> p2
    Point(x=4, y=2, z=3)

    Bonus 1

    For the first bonus, I'd like you to allow Point objects to be added and subtracted from each other
    >>> p1 = Point(1, 2, 3)
    >>> p2 = Point(4, 5, 6)
    >>> p1 + p2
    Point(x=5, y=7, z=9)
    >>> p3 = p2 - p1
    >>> p3
    Point(x=3, y=3, z=3)

    Bonus 2

    For the second bonus, I'd like you to allow Point objects to be scaled up and down by numbers
    >>> p1 = Point(1, 2, 3)
    >>> p2 = p1 * 2
    >>> p2
    Point(x=2, y=4, z=6)

    >>> 3 * p1
    Point(x=3, y=6, z=9)

    Bonus 3

    For the third bonus, I'd like you to allow Point objects to be unpacked using multiple assignment like this:

    >>> p1 = Point(1, 2, 3)
    >>> x, y, z = p1
    >>> (x, y, z)
    (1, 2, 3)
    """

    def __init__(self, x, y, z):
        self.x: float = x
        self.y: float = y
        self.z: float = z

    def __iter__(self):
        yield from vars(self).values()

    def __eq__(self, other):
        if not isinstance(other, self.__class__): raise NotImplementedError
        return vars(self) == vars(other)

    def __add__(self, other):
        # Could also use the same approach as __sub__
        if not isinstance(other, self.__class__): raise NotImplementedError
        return self.__class__(*(map(sum, zip(self, other))))

    def __sub__(self, other):
        if not isinstance(other, self.__class__): raise NotImplementedError
        return self.__class__(*(operator.sub(*_) for _ in zip(self, other)))

    def __mul__(self, other):
        if not isinstance(other, (int, float)): raise NotImplementedError
        return self.__class__(*(_ * other for _ in self))

    __rmul__ = __mul__

    def __repr__(self):
        sig = ", ".join(f"{k}={v}" for k, v in vars(self).items())
        return self.__class__.__name__ + f"({sig})"


if __name__ == "__main__":
    import doctest
    doctest.testmod(verbose=True)