如何在python中使两个对象具有相同的id？

Question

如果我有以下课程：

class Point(object):
    def __init__(self, x, y):
        self.x = x
        self.y = y

有两个对象：

^{pr2}$

如何修改类点使id(a) == id(b)？在

Answer 1

您需要有一个对象的全局字典，并通过工厂函数（或自定义的__new__）获取它们，请参阅其他答案）。另外，考虑使用^{}，这样就不会不必要地用不再需要的对象填满内存。在

from weakref import WeakValueDictionary


class _Point(object):
    def __init__(self, x, y):
        self.x = x
        self.y = y

# Cache of Point objects the program currently uses
_points = WeakValueDictionary()


def Point(x, y):
    """Create a Point object"""
    # Note that this is a function (a "factory function")
    # You can also override Point.__new__ instead
    try:
        return _points[x, y]
    except KeyError:
        _points[x, y] = point = _Point(x, y)
        return point


if __name__ == '__main__':
    # A basic demo
    print Point(1, 2)
    print id(Point(1, 2))
    print Point(2, 3) == Point(2, 3)

    pt_2_3 = Point(2, 3)

    # The Point(1, 2) we created earlier is not needed any more.
    # In current CPython, it will have been been garbage collected by now
    # (but note that Python makes no guarantees about when objects are deleted)
    # If we create a new Point(1, 2), it should get a different id

    print id(Point(1, 2))

请注意，namedtuple不能与WeakValueDictionary一起使用。在