[Numpy-discussion] dtype '|S0' not understood

David Warde-Farley wardefar at iro.umontreal.ca
Sun Oct 7 00:35:02 EDT 2012

On Wed, Oct 3, 2012 at 1:58 PM, Will Lee <lee.will at gmail.com> wrote:
> This seems to be a old problem but I've recently hit with this in a very
> random way (I'm using numpy 1.6.1).  There seems to be a ticket (1239) but
> it seems the issue is unscheduled.   Can somebody tell me if this is fixed?
> In particular, it makes for a very unstable behavior when you try to
> reference something from a string array and pickle it across the wire.  For
> example:
> In [1]: import numpy
> In [2]: a = numpy.array(['a', '', 'b'])
> In [3]: import cPickle
> In [4]: s = cPickle.dumps(a[1])
> In [5]: cPickle.loads(s)
> ---------------------------------------------------------------------------
> TypeError                                 Traceback (most recent call last)
> /auto/cnvtvws/wlee/fstrat/src/<ipython-input-5-555fae2bd4f5> in <module>()
> ----> 1 cPickle.loads(s)
> TypeError: ('data type not understood', <type 'numpy.dtype'>, ('S0', 0, 1))
> Note that if you reference a[0] and a[2], it would work, so you're in the
> case where sometimes it'd work but sometimes it won't.  Checking for this
> case in the code and work around it would really be a pain.

Hi Will,

Yes, this has been waiting on the bug tracker for a long while. I'll
resubmit my patch as a pull request to see if we can't get this fixed
up soon...


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