Travis Oliphant schrieb: > Sturla Molden wrote: >> >>> x = numpy.arange(100).reshape((1,10,10)) >> >> >>> x[0,:,numpy.arange(5)].shape >> (5, 10) >> >> >>> x[:,:,numpy.arange(5)].shape >> (1, 10, 5) >> >> >> It looks like a bug that needs to be squashed. >> > > These are both correct. See my previous posts about the rule. > > The first case is exactly the example we saw before: we start with a > (1,10,10)-shaped array and replace the first and last-dimension > (1,10)-shaped array with a (5,)-shaped array. Not having a clear place > to put the extracted (5,)-shaped subspace, it is tacked on to the front. > > In the second example, the last-dimension (10,)-shaped sub-space is > replaced with a (5,)-shaped sub-space. There is no ambiguity in this > case and the result is a (1,10,5)-shaped array. > > There is no bug here. Perhaps unexpected behavior with "advanced > indexing" combined with single-integer indexing in separated dimensions > but no bug. The result, does follow an understandable and generalizable > rule. > >
Thanks for the explanation. Maybe some of these examples could be added to the relevant section of the book. Although I must say I'm glad that I currently don't need to use this stuff, I'm not sure I would get it right :-) cheers, sven _______________________________________________ Numpy-discussion mailing list Numpy-discussion@scipy.org http://projects.scipy.org/mailman/listinfo/numpy-discussion
