[Numpy-discussion] Comparison of arrays
Nils Wagner
nwagner at iam.uni-stuttgart.de
Mon Feb 9 04:00:05 EST 2009
On Mon, 9 Feb 2009 09:45:02 +0100
Francesc Alted <faltet at pytables.org> wrote:
> A Monday 09 February 2009, Nils Wagner escrigué:
>> Hi all,
>>
>> I have two integer arrays of different shape, e.g.
>>
>> >>> a
>>
>> array([ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10])
>>
>> >>> b
>>
>> array([ 3, 4, 5, 6, 7, 8, 9, 10])
>>
>> How can I extract the values that belong to the array a
>> exclusively i.e. array([1,2]) ?
>
> One possible, fast solution is using Python sets:
>
> In [45]: np.array(list(set(a) ^ set(b)))
> Out[45]: array([1, 2])
>
> Although this is suboptimal for very large arrays as it
>needs temporary
> space.
>
> Cheers,
>
> --
>Francesc Alted
Thank you very much for your prompt response.
Nils
More information about the NumPy-Discussion
mailing list