On Tue, 2017-12-12 at 14:19 +0100, Joe wrote: > Ah, ok, now that I knew what to look for I guess I found it: > > "If the number of objects in the selection tuple is less than N , > then : > is assumed for any subsequent dimensions." > > https://docs.scipy.org/doc/numpy-1.13.0/reference/arrays.indexing.htm > l > > This is the one, right? >
Yeah, plus if it is not a tuple, it actually behaves the same as a tuple, e.g. `arr[obj]` is identical to `arr[obj,]` (or `arr[(obj,)]` which is the same). There are some weird exception when obj is a list a sequence but not an array. Note also that while everything has an implicit `, ...` at the end of indexing, if you have exactly as many integers to index as dimensions you get a scalar, if you would add the Ellipsis you would get an array back. Anyway, too many weird details for day to day stuff :). And all of that should be covered in the docs? - Sebastian > > Am 12.12.2017 09:09 schrieb Nathaniel Smith: > > On Tue, Dec 12, 2017 at 12:02 AM, Joe <solar...@posteo.org> wrote: > > > Hi, > > > > > > question says it all. I looked through the basic and advanced > > > indexing, > > > but I could not find the rule that is applied to make > > > x[np.newaxis,:] and x[np.newaxis] the same. > > > > I think it's the general rule that all indexing expressions have an > > invisible "..." on the right edge. For example, x[i][j][k] is an > > inefficient and IMO somewhat confusing way to write x[i, j, k], > > because x[i][j][k] is interpreted as: > > > > -> x[i, ...][j, ...][k, ...] > > -> x[i, :, :][j, :][k] > > > > That this also applies to newaxis is a little surprising, but I > > guess > > consistent. > > > > -n > > _______________________________________________ > NumPy-Discussion mailing list > NumPy-Discussion@python.org > https://mail.python.org/mailman/listinfo/numpy-discussion >
signature.asc
Description: This is a digitally signed message part
_______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@python.org https://mail.python.org/mailman/listinfo/numpy-discussion
