It is great to hear that this might be useful. I would LOVE to create a PR on this idea and contribute back to numpy...but let's not get ahead of ourselves :-)
Regarding the name, I kinda like "unpad" since it relates directly to "pad", analogous to "ravel" and "unravel" for instance. Or maybe "depad". Although, it's possible to use this on any array, not just a previously padded one, so maybe tying it too directly to "pad" is not right, in which case "trim" and "crop" are both perfect. I must admit that I find it odd that these functions are not in numpy already. I just searched the docs and they show up as keyword args for a few functions but are otherwise conspicuously absent. Also, funnily, there is a link to "padding arrays" but it is basically empty: https://numpy.org/doc/stable/reference/routines.padding.html. Alternatively, I don't hate the idea of passing negative pad widths into "pad". I actually tried this at one point to see if there was a hidden functionality there, to no avail. BTW, we just adding a custom "unpad" function to our PoreSpy package for this purpose: https://github.com/PMEAL/porespy/blob/dev/porespy/tools/_unpadfunc.py On Mon, Apr 12, 2021 at 9:15 PM Stephan Hoyer <sho...@gmail.com> wrote: > On Mon, Apr 12, 2021 at 5:12 PM Jeff Gostick <jgost...@gmail.com> wrote: > >> 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. >> > > Indeed, this is a fair question. > > Given that this is not entirely trivial to write correctly, I think it > would be reasonable to add the inverse operation for pad() into NumPy. This > is generally better than encouraging users to write their own thing. > > From a naming perspective, here are some possibilities: > unpad > trim > crop > > I think "trim" would be pretty descriptive, probably slightly better than > "unpad." > _______________________________________________ > NumPy-Discussion mailing list > NumPy-Discussion@python.org > https://mail.python.org/mailman/listinfo/numpy-discussion >
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