[Numpy-discussion] possible bug with numpy.object_

Travis Oliphant oliphant.travis at ieee.org
Thu Aug 31 08:40:28 CDT 2006


Fernando Perez wrote:
> On 8/30/06, Stefan van der Walt <stefan at sun.ac.za> wrote:
>
>   
>> The current behaviour makes sense, but is maybe not consistent:
>>
>> N.array([],dtype=object).size == 1
>> N.array([[],[]],dtype=object).size == 2
>>     
>
> Yes, including one more term in this check:
>
> In [5]: N.array([],dtype=object).size
> Out[5]: 1
>
> In [6]: N.array([[]],dtype=object).size
> Out[6]: 1
>
> In [7]: N.array([[],[]],dtype=object).size
> Out[7]: 2
>
> Intuitively, I'd have expected the answers to be 0,1,2, instead of 1,1,2.
>
>   

What about

N.array(3).size

N.array([3]).size

N.array([3,3]).size

Essentially, the [] is being treated as an object when you explicitly 
ask for an object array in exactly the same way as 3 is being treated as 
a number in the default case.  It's just that '[' ']' is "also" being 
used as the dimension delimiter and thus the confusion.

It is consistent.   It's a corner case, and I have no problem fixing the 
special-case code running when dtype=object so that array([], 
dtype=object) returns an empty array, if that is the consensus.

-Travis



> Cheers,
>
> f
>
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