[Numpy-discussion] Masked arrays and pickle/unpickle

Hans Meine meine@informatik.uni-hamburg...
Fri Nov 7 06:11:18 CST 2008

On Thursday 17 July 2008 19:41:51 Anthony Floyd wrote:
> > > What I need to know is how I can trick pickle or Numpy to
> >
> > put the old class into the new class.
> >
> > If you have an example data-file, send it to me off-list and I'll
> > figure out what to do.  Maybe it is as simple as
> >
> > np.core.ma = np.oldnumeric.ma
> Yes, pretty much.  We've put ma.py into numpy.core where ma.py is
> nothing more than:
> import numpy.oldnumeric.ma as ma
> class MaskedArray(ma.MaskedArray):
>     pass
> It works, but becomes a bit of a headache because we now have to
> maintain our own numpy package so that all the developers get these
> three lines when they install numpy.

Did you try changing the pickled data?  IIRC you could simply search&replace, 
since the class name is at the beginning of the representation in clear text.
(I see that this a hack, too but it saves you from having to maintain your own 


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