Re: [Pytables-users] clean up Table addressing?

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

A Dilluns 31 Gener 2005 19:21, Norbert Nemec va escriure:
> > That sounds reasonable. What about making rows --> rowlist and
> > columns --> columnlist?
>
> How about rowselect and colselect? Probably a matter of taste. 'list' is
> fine with me as well.

I still prefer rowlist and columnlist. Although selectrows and
selectcolums might be nice as well.

> OK, I agree that retrieving out of order is a killer. Still - if I give a
> list of rows to read, I would expect the result to be ordered in the same
> way. Maybe, the code could check whether the list is ordered and throw an
> error otherwise? Checking, whether a list is sorted is relatively
> inexpensive.
> (OK, sorting an already sorted list is inexpensive as well, but still, I
> don't like the idea of silently changing the order of rows in a request.)

I see your point. Mmm, perhaps raising a warning in case the list is
unordered would be better (in the end, this operation would be
perfectly valid).

> Alternatively, one could sort the list first and use the permutation of t=
he
>
>  rowselect,permutation =3D zip(sorted(zip(rowselect,range(len(rowselect))=
)))
>  result =3D read_rows(rowselect)
>  dummy,result =3D zip(sorted(zip(permutation,result)))
>  return result
>
> but that's probably overkill...

No, numarray can do this very efficently for NumArray objects. The
problem could be re-ordering the resulting RecArray, that can be a bit
more inefficient, but in the long run, that maybe worth the effort for
most of cases. Good idea!

Cheers and good luck!,

=2D-=20
>qo<   Francesc Altet =A0 =A0 http://www.carabos.com/
V =A0V   C=E1rabos Coop. V. =A0=A0Enjoy Data
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