[Numpy-discussion] np.unique for one bi-dimensional array

eat e.antero.tammi@gmail....
Tue Jul 24 19:02:46 CDT 2012


Hi,

On Wed, Jul 25, 2012 at 1:09 AM, Giuseppe Amatulli <
giuseppe.amatulli@gmail.com> wrote:

> Hi,
>
> would like to identify unique pairs of numbers in two arrays o in one
> bi-dimensional array, and count the observation
>
> a_clean=array([4,4,5,4,4,4])
> b_clean=array([3,5,4,4,3,4])
>
> and obtain
> (4,3,2)
> (4,5,1)
> (5,4,1)
> (4,4,2)
>
> I solved with tow loops but off course there will be a fast solution
> Any idea?
> what about using np.unique for one bi-dimensional array?
>
According the docs
http://docs.scipy.org/doc/numpy/reference/generated/numpy.unique.html np.unique
will flatten the input to 1D array.

However, perhaps something like the following lines will help you:
In []: lot= zip(a_clean, b_clean)
In []: lot
Out[]: [(4, 3), (4, 5), (5, 4), (4, 4), (4, 3), (4, 4)]
In []: [[x, lot.count(x)] for x in set(lot)]
Out[]: [[(4, 5), 1], [(5, 4), 1], [(4, 4), 2], [(4, 3), 2]]


My 2 cents,
-eat

>
> In bash I usually unique command
>
> thanks in advance
> Giuseppe
>
> --
> Giuseppe Amatulli
> Web: www.spatial-ecology.net
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