[Numpy-discussion] recarray field access asymmetry
David Gowers (kampu)
Wed Feb 15 02:25:47 CST 2012
Thanks for your prompt response.
On Wed, Feb 15, 2012 at 6:40 PM, Benjamin Root <email@example.com> wrote:
>> Rather than recarrays, I just use structured arrays like so:
>> A = np.array([(0, 0), (0, 0), (0, 0), (0, 0)],
>> dtype=[('x', '<u2'), ('y', '<u2')])
>> I can then do:
>> This allows me to slice and access the data any way I want. I have even
>> been able to use this dictionary idiom to format strings and such.
>> Does that help?
>> Ben Root
> Sorry, didn't see that you have nested dtypes. Is there a particular reason
> why you need record arrays over structured arrays?
It's really a matter of how much dereferencing of substructures
occurs, and how much extra typing that turns into.
A['x'] -> 4 extra characters per field lookup, vs
A.x / A.x -> 1 extra character per field lookup.
There's also an issue of highlighting -- I'd prefer x to be
highlighted in the style of an attribute, not a string, when I'm
editing source. A['x'] obviously precludes this.
I have considered normal structured arrays -- repeatedly, after being
frustrated by this recarray behaviour.
However, I'd like to achieve some kind of resolution here -- even if
it is just this unexpected behaviour being properly documented.
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