Pickle all attributes except one

Question

What is the best way to write a __getstate__ method that pickles almost all of an object\'s attributes, but excludes a few?

I have an object wi

Answer 1

__slots__ solution

If you are using slots, you can avoid repeating members to exclude with:

class C(object):
    _pickle_slots = ['i']
    __slots__ = _pickle_slots + ['j']
    def __init__(self, i, j):
        self.i = i
        self.j = j
    def __getstate__(self):
        return (None, {k:getattr(self, k) for k in C._pickle_slots })

o = pickle.loads(pickle.dumps(C(1, 2), -1))

# i is there
assert o.i == 1

# j was excluded
try:
    o.j
except:
    pass
else:
    raise

Tested in Python 2.7.6.