On Feb 8, 2012, at 11:17 AM, josef.p...@gmail.com wrote: > On Wed, Feb 8, 2012 at 10:29 AM, Sturla Molden <stu...@molden.no> wrote: >> On 08.02.2012 15:49, Travis Oliphant wrote: >> >>> This sort of thing would take time, but is not out of the question in my >>> mind because I suspect the number of users and use-cases of "broadcasted" >>> fancy-indexing is small. > > I think I use it quite a bit, and I like that the broadcasting in > indexing is as flexible as the broadcasting of numpy arrays > themselves. > > x[np.arange(len(x)), np.arange(len(x))] gives the diagonal for example. > > or picking a different element from each column, (I don't remember > where I used that) > > It is surprising at first and takes some getting used to, but I think > it's pretty nice. On the other hand, I always avoid mixing slices and > indexes because of "strange" results.
It actually is pretty nice once you understand it. Mixing of fancy indexing and slicing is only nice in special circumstances. I think we would have been better off if rather than move the subspace to the beginning of the array, NumPy raised an error in that case. That would be a useful change. -Travis > > Josef > > >> >> In Matlab this (misfeature?) is generally used to compensate for the >> lack of broadbasting. So many Matlab programmers manually broadcast by >> fancy indexing with an array of (boolean) ones (it's less verbose than >> reshape). But with broadcasting for binary array operators (NumPy and >> Fortran 90), this is never needed. >> >> Sturla >> _______________________________________________ >> NumPy-Discussion mailing list >> NumPy-Discussion@scipy.org >> http://mail.scipy.org/mailman/listinfo/numpy-discussion > _______________________________________________ > NumPy-Discussion mailing list > NumPy-Discussion@scipy.org > http://mail.scipy.org/mailman/listinfo/numpy-discussion _______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
