[SciPy-dev] 'nuther Q re: chararray

David Goldsmith d_l_goldsmith at yahoo.com
Tue Aug 11 19:50:46 EDT 2009


Doh! Jackpot, thanks!

DG

--- On Tue, 8/11/09, josef.pktd at gmail.com <josef.pktd at gmail.com> wrote:

> From: josef.pktd at gmail.com <josef.pktd at gmail.com>
> Subject: Re: [SciPy-dev] 'nuther Q re: chararray
> To: "SciPy Developers List" <scipy-dev at scipy.org>
> Date: Tuesday, August 11, 2009, 4:36 PM
> On Tue, Aug 11, 2009 at 7:30 PM,
> <d_l_goldsmith at yahoo.com>
> wrote:
> > >From "Guide to Numpy":
> >
> > "Perhaps the easiest way to create a chararray is to
> use self.view(chararray) where self is an ndarray of string
> or unicode data-type."
> >
> > OK, but what is "(chararray)"?  In particular, my
> best guesses yielded:
> >
> >>>> c = np.empty((2,2), dtype=unicode)
> >>>> c
> > array([[u'\u0f01\ude68', u'\uf880\udc00'],
> >        [u'\uf0c0\udc00', u'\u5300']],
> >       dtype='<U1')
> >>>> c.view(chararray) # can't mean it
> literally, right?
> > Traceback (most recent call last):
> >   File "<stdin>", line 1, in <module>
> > NameError: name 'chararray' is not defined
> >>>> c.view(C) # does the expression assign a
> value to the argument?
> > Traceback (most recent call last):
> >   File "<stdin>", line 1, in <module>
> > NameError: name 'C' is not defined
> >>>> C = np.chararray((2,2)) # this is most
> logical
> >>>> c.view(C)
> > Traceback (most recent call last):
> >   File "<stdin>", line 1, in <module>
> > ValueError: Dtype must be a numpy data-type
> >
> > So, what does Travis mean?  Thanks,
> >
> > DG
> >
> >
> 
> with this type of error I usually check the namespace
> 
> >>> import numpy as np
> >>> np.chararray
> <class 'numpy.core.defchararray.chararray'>
> >>> c = np.empty((2,2), dtype=unicode)
> >>> c.view(np.chararray)
> chararray([['', u'\x04'],
>        [u'\x01',
> u'\uf3db\ude20']],
>       dtype='<U1')
> 
> But I have no idea what chararrays are
> 
> Josef
> 
> >
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> >
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