Ah I see. Well, Cython's coming support won't be much help either then...(if 
you want to, say, wrap a sparse matrix lib or similar).

Anyway:
 - Don't do arr[i][j], do arr[i,j].
 - Do override __getitem__! (if necesarry in a new object returned from a 
proprty, but in this case I don't see any need for properties)
 - Slices etc are no problem, you can check the index parameter to __getitem__ 
for slice objects.

Yes, you must manually implement slices etc., but if NumPy doesn't cover your 
case this follows anyway! -- it's  not like Python or Cython would be able to 
guess what a slice should represent or how it should be implemented in your 
more complex problems.

Dag Sverre Seljebotn
-----Original Message-----
From: Mattia Ziulu <[email protected]>
Date: Friday, Aug 28, 2009 3:50 pm
Subject: Re: [Cython] Expose a *float element to Python namespace
To: [email protected]: [email protected]


>On Fri, Aug 28, 2009 at 3:29 PM, Dag Sverre Seljebotn 
><[email protected]> wrote:
>  Two answers:
>  1) In about half a year, there will likely be a released version of Cython 
> with built in capability to do this kind of wrapping.
>
>
>This is awesome!  
>
>  2) NumPy NumPy NumPy! Doing this without using NumPy is a waste of time IMO. 
> Use the PyArray_New... function in the C api to create array backed by your C 
> struct. (I remember posting a howto to Jon Olav Vik here on the list around 
> June).
>
>
>No can do. Or better yet, yes could do, but the whole point here is that my 
>MatrixFloat gimmick is all a big test for something a lot more complicated and 
>generalized, where Numpy wouldn't be useful at all. Let's just say that I'm 
>using this 'project' to wrap my mind around this whole (and for me new) world 
>of wrapping and exposing and whatnot, and being a matrix class something 
>pretty easy to set up (in a fairly basic way anyway) I choose to implement 
>this.
> I've looked at numpy for some inspiration though, both docs and source code, 
> but there are not a lot of useful things in it that could be useful in this 
> context too, I'm afraid.
>

_______________________________________________
Cython-dev mailing list
[email protected]
http://codespeak.net/mailman/listinfo/cython-dev

Reply via email to