in a pickle

[Ethan Furman]

On 03/06/2019 10:30 AM, duncan smith wrote:

>  I've been trying to figure out why one of my classes can be
> pickled but not unpickled. (I realise the problem is probably with the
> pickling, but I get the error when I attempt to unpickle.)
>
> A relatively minimal example is pasted below.
>
>
> --> import pickle
> --> class test(dict):
> ...    def __init__(self, keys, shape=None):
> ...        self.shape = shape
> ...        for key in keys:
> ...            self[key] = None
> ...    def __setitem__(self, key, val):
> ...        print (self.shape)
> ...        dict.__setitem__(self, key, val)
> ...
> --> x = test([1,2,3])
> None
> None
> None
> --> s = pickle.dumps(x)
> --> y = pickle.loads(s)
> Traceback (most recent call last):
>    File "<pyshell#114>", line 1, in <module>
>      y = pickle.loads(s)
>    File "<pyshell#111>", line 8, in __setitem__
>      print (self.shape)
> AttributeError: 'test' object has no attribute 'shape'

It seems to me the problem only exists because you are trying to print `self.shape` -- stop printing it, and everything works normally.

What problem are you actually trying to solve?

--
~Ethan~