Pickle translation

Skip Montanaro skip at pobox.com
Wed Jul 11 22:55:45 CEST 2001


    William> So, are there any tools to translate 1.5.2 pickles to 2.x
    William> versions of the pickle format?  

I wasn't aware that 2.x couldn't read pickles created by 1.5.2.  I just
tried a simple example without any problem (sorry, 1.6 is as far as I go
back on my local machine):

    % python1.6
    Python 1.6 (#1, Jul 10 2001, 17:24:51)  [GCC 2.96 20000731 (Linux-Mandrake 8.0 2.96-0.48mdk)] on linux2
    Copyright (c) 1995-2000 Corporation for National Research Initiatives.
    All Rights Reserved.
    Copyright (c) 1991-1995 Stichting Mathematisch Centrum, Amsterdam.
    All Rights Reserved.
    >>> class foo:
    ...    pass
    ... 
    >>> a = foo()
    >>> a.x = 1
    >>> b = ["a",1,(0,1,2)]
    >>> t = (a,b)
    >>> d = {"key":t}
    >>> d
    {'key': (<__main__.foo instance at 8239bf8>, ['a', 1, (0, 1, 2)])}
    >>> import pickle
    >>> f = open("pickle.dat", "w")
    >>> pickle.dump.__doc__
    >>> pickle.dump(d, f)
    >>> f.close()
    >>> 
    % python2.1
    Python 2.1.1c1 (#13, Jul 10 2001, 17:30:38) 
    [GCC 2.96 20000731 (Linux-Mandrake 8.0 2.96-0.48mdk)] on linux2
    Type "copyright", "credits" or "license" for more information.
    >>> class foo:
    ...    pass
    ... 
    >>> import pickle
    >>> d = pickle.load(open("pickle.dat"))
    >>> d
    {'key': (<__main__.foo instance at 0x82319cc>, ['a', 1, (0, 1, 2)])}

I see a comment in the pickle lib ref manual section about a change to
pickle's behavior that was introduced in 1.5b2 (significantly before 1.5.2),
but nothing about 1.5.2->2.x incompatibilities.  Can you be more specific
about what's not working for you?

-- 
Skip Montanaro (skip at pobox.com)
(847)971-7098




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