I guess I should have clarified that I was inquiring about proposing a 'feature request'. The github site suggested I open a discussion on this list first. There are several ways to effectively unpad an array as has been pointed out, but they all require more than a little bit of thought and care, are dependent on array shape, and honestly error prone. It would be very valuable to me to have such a 'predefined' function, so I was wondering if (a) I was unaware of some function that already does this and (b) if I'm alone in thinking this would be useful.
On Mon, Apr 12, 2021 at 7:42 PM Aaron Meurer <asmeu...@gmail.com> wrote: > On Mon, Apr 12, 2021 at 2:29 PM Stephan Hoyer <sho...@gmail.com> wrote: > > > > The easy way to unpad an array is by indexing with slices, e.g., > x[20:-4] to undo a padding of [(20, 4)]. Just be careful about unpadding > "zero" elements on the right hand side, because Python interprets an ending > slice of zero differently -- you need to write something like x[20:] to > undo padding by [(20, 0)]. > > You can use x[20:x.shape[0] - 4] to avoid this inconsistency. Or > construct the slice based on the original unpadded shape > (x[20:20+orig_x.shape[0]]). > > Aaron Meurer > > > > > > > On Mon, Apr 12, 2021 at 1:15 PM Jeff Gostick <jgost...@gmail.com> wrote: > >> > >> I often find myself padding an array to do some processing on it (i.e. > to avoid edge artifacts), then I need to remove the padding. I wish there > was either a built in "unpad" function that accepted the same arguments as > "pad", or that "pad" accepted negative numbers (e.g [-20, -4] would undo a > padding of [20, 4]). This seems like a pretty obvious feature to me so > maybe I've just missed something, but I have looked through all the open > and closed issues on github and don't see anything related to this. > >> > >> > >> Jeff G > >> > >> _______________________________________________ > >> NumPy-Discussion mailing list > >> NumPy-Discussion@python.org > >> https://mail.python.org/mailman/listinfo/numpy-discussion > > > > _______________________________________________ > > NumPy-Discussion mailing list > > NumPy-Discussion@python.org > > https://mail.python.org/mailman/listinfo/numpy-discussion > _______________________________________________ > NumPy-Discussion mailing list > NumPy-Discussion@python.org > https://mail.python.org/mailman/listinfo/numpy-discussion >
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