Re: [Pytables-users] Some method like a "table.readWhereSorted"

[Julio T. <jul...@gm...>]

Hi Anthony

Thanks for adding this issue.

Is there a way to use CS indexes to get the row coordinates satisfying a
simple condition sorted by the column in the condition? I would like to
avoid using numpy.sort() since the sorting order is probably already
available within the index information.

My condition is simply (timestamp >= %d) & (timestamp <= %d)" % (ts1, ts2)

If you could please give me some guidelines so that I could put together
such a method, that would be great.

Julio


(like using getWhereList()), but using an index to get the coordinate list
ordered by column indexes to get the coordinates ? I nhas a
*sort*parameter that uses numpy.sort() to do the work, and that
readSorted() uses
a full index to get the sorted sequence. I couldn't make complete sense yet
of "chunkmaps" being passed to numexpr evaluator inside _where().


On Thu, Apr 11, 2013 at 1:14 PM, Anthony Scopatz <sc...@gm...> wrote:

> Thanks for bringing this up, Julio.
>
> Hmm I don't think that this exists currently, but since there are
> readWhere() and readSorted() it shouldn't be too hard to implement.  I have
> opened issue #225 to this effect.  Pull requests welcome!
>
> https://github.com/PyTables/PyTables/issues/225
>
> Be Well
> Anthony
>
>
> On Wed, Apr 10, 2013 at 1:02 PM, Dr. Louis Wicker <lou...@no...>wrote:
>
>> I am also interested in the this capability, if it exists in some way...
>>
>> Lou
>>
>> On Apr 10, 2013, at 12:35 PM, Julio Trevisan <jul...@gm...>
>> wrote:
>>
>> > Hi,
>> >
>> > Is there a way that I could have the ability of readWhere (i.e.,
>> specify condition, and fast result) but also using a CSIndex so that the
>> rows come sorted in a particular order?
>> >
>> > I checked readSorted() but it is iterative and does not allow to
>> specify a condition.
>> >
>> > Julio
>> >
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