[Numpy-discussion] Creating multirow numpy rec.arrays

[Francesc A. <fa...@ca...>]

Hi,

This exposes a weird behaviour when building heterogeneous arrays in
numpy:

In [85]: xcol =3D numpy.ones((3,2), 'int32')

In [86]: numpy.array([(xcol[0],)], dtype=3D[('x','i4', (2,))])
Out[86]: array([(array([1, 1]),)], dtype=3D(void,8))

So far so good. Now:

In [89]: numpy.array([xcol], dtype=3D[('x','i4', (2,))])
<ERROR: expected a readable buffer object>
array([[[(array([-1208633192, -1208633192]),), (array([15, 15]),)],
        [(array([  0, 185]),), (array([         18, -1208633016]),)],
        [(array([480,  21]),), (array([21, 21]),)]]], dtype=3D(void,8))

While I'd expect:

In [89]: numpy.array([xcol], dtype=3D[('x','i4', (2,))])
Out[89]: array([(array([1, 1]),
                (array([1, 1]),
		(array([1, 1]))], dtype=3D(void,8))

Also, for the whishlist: It would be nice if one can specify the shape
of the array to be built in the factory itself. I mean, allowing
something like:

In [90]: numpy.array([xcol], dtype=3D[('x','i4', (2,))], shape=3D2)
Out[90]: array([(array([1, 1]),
		(array([1, 1]))], dtype=3D(void,8))

Cheers,

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>0,0<   Francesc Altet =A0 =A0 http://www.carabos.com/
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