所有成员变量的Python__repr__

实现__repr__了一类Foo有成员变量x和y,是有办法来自动填充字符串？不起作用的示例:

class Foo(object):
    def __init__(self, x, y):
        self.x = x
        self.y = y
    def __repr__(self):
        return "Foo({})".format(**self.__dict__)

>>> foo = Foo(42, 66)
>>> print(foo)
IndexError: tuple index out of range

而另一个:

from pprint import pprint
class Foo(object):
    def __init__(self, x, y):
        self.x = x
        self.y = y
    def __repr__(self):
        return "Foo({})".format(pprint(self.__dict__))

>>> foo = Foo(42, 66)
>>> print(foo)
{'x': 42, 'y': 66}
Foo(None)

是的我可以将方法定义为

    def __repr__(self):
        return "Foo({x={}, y={}})".format(self.x, self.x)

但是当有许多成员变量时,这会变得乏味.

当我想要这样的东西时,我用它作为mixin:

class SimpleRepr(object):
    """A mixin implementing a simple __repr__."""
    def __repr__(self):
        return "<{klass} @{id:x} {attrs}>".format(
            klass=self.__class__.__name__,
            id=id(self) & 0xFFFFFF,
            attrs=" ".join("{}={!r}".format(k, v) for k, v in self.__dict__.items()),
            )

它给出了类名,(缩短的)id和所有属性.