pickling the objects returned by array.array()
John Machin
sjmachin at lexicon.net
Thu Sep 1 09:48:24 EDT 2005
Googling for "pickle array" in comp.lang.python yields old messages that
show a PickleError -- plus one message where Alex Martelli writes "I am
but an egg" :O)
Looks like arrays are NOW (2.4.1) pickleable but not unpickleable -- see
below.
I appreciate that arrays are inherently not pickleable because of the
type code.
However:
(1) Anyone know why/when the world changed?
(2) If we had alternative constructors like array.iarray(contents) in
parallel to array.array('i', contents), those objects could be
pickled/unpickled -- yes/no?
Cheers,
John
====================
Python 2.4.1 (#65, Mar 30 2005, 09:13:57) [MSC v.1310 32 bit (Intel)] on
win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import pickle, array
>>> class Foo(object):
... pass
...
>>> foo = Foo()
>>> foo.ia = array.array('i', [3,2,1])
>>> foo.ia
array('i', [3, 2, 1])
>>> s = pickle.dumps(foo, -1)
>>> bar = pickle.loads(s)
Traceback (most recent call last):
File "<stdin>", line 1, in ?
File "C:\Python24\lib\pickle.py", line 1394, in loads
return Unpickler(file).load()
File "C:\Python24\lib\pickle.py", line 872, in load
dispatch[key](self)
File "C:\Python24\lib\pickle.py", line 1097, in load_newobj
obj = cls.__new__(cls, *args)
TypeError: array() takes at least 1 argument (0 given)
===========
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