[Numpy-discussion] Is this a bug?

Robert Kern robert.kern@gmail....
Tue May 27 16:07:54 CDT 2008


On Tue, May 27, 2008 at 3:15 PM, Travis E. Oliphant
<oliphant@enthought.com> wrote:
> Charles R Harris wrote:
>>
>> On Tue, May 27, 2008 at 1:31 PM, Travis E. Oliphant
>> <oliphant@enthought.com <mailto:oliphant@enthought.com>> wrote:
>>
>>     Charles R Harris wrote:
>>     > I vaguely recall this generated an array from all the characters.
>>     >
>>     > In [1]: array('123', dtype='c')
>>     > Out[1]:
>>     > array('1',
>>     >       dtype='|S1')
>>     This may be a bug.
>>
>>      >>> import Numeric
>>      >>> Numeric.array('123','c')
>>     array([1, 2, 3],'c')
>>
>>     My memory of the point of 'c' was to mimic Numeric's behavior for
>>     character arrays.
>>
>>
>> Current behavior after fix is
>>
>> In [1]: array('123','c')
>> Out[1]:
>> array(['1', '2', '3'],
>>       dtype='|S1')
>>
>> Is that correct, then?
> Yes.

Can we make it so that dtype('c') is preserved instead of displaying
'|S1'? It does not behave the same as dtype('|S1') although it
compares equal to it.

In [90]: dtype('c')
Out[90]: dtype('|S1')

In [91]: array('123', dtype='c')
Out[91]:
array(['1', '2', '3'],
      dtype='|S1')

In [92]: array('123', dtype=dtype('c'))
Out[92]:
array(['1', '2', '3'],
      dtype='|S1')

In [93]: array('123', dtype=dtype('|S1'))
Out[93]:
array('1',
      dtype='|S1')

In [94]: array('456', dtype=array('123', dtype=dtype('c')).dtype)
Out[94]:
array(['4', '5', '6'],
      dtype='|S1')

In [95]: dtype('c') == dtype('|S1')
Out[95]: True


-- 
Robert Kern

"I have come to believe that the whole world is an enigma, a harmless
enigma that is made terrible by our own mad attempt to interpret it as
though it had an underlying truth."
 -- Umberto Eco


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