If NumPy were to make a move on the deprecation, then I think it would be reasonable to change the standard from
> If the array instance is not two-dimensional, an error should be raised. to “if the array instance is not two-dimensional, behaviour should match `.mT`, or an error should be raised.” > On 14 Apr 2025, at 08:35, Sebastian Berg <[email protected]> wrote: > > On Sat, 2025-04-12 at 10:10 +0000, Mateusz Sokol wrote: >> Hi all! >> >> The Array API standard states that `T` property should only be >> applied to 2-dimensional arrays, in all other cases it should raise >> an error: >> https://data-apis.org/array-api/latest/API_specification/generated/array_api.array.T >> >> To ensure that NumPy also follows this rule, I opened a PR that >> raises a warning for `arr.T` for non-2-dimensional arrays and >> scalars: https://github.com/numpy/numpy/pull/28678 > > > There was once a surprising amount of resistance to doing this exact > change a long time ago in NumPy and that is exactly why it never > happened earlier and that is why we have `.mT` and not just `.T` to > begin with. > > I am still happy with slowly deprecating it with a message to use > `arr.transpose()`, `np.moveaxis()`, or `.mT` when it is applies. > Maybe making sure that `.T` keeps working at least for 2-D, and think > about what to do for 1-D (probably an error), although I am not sure > about this unless there is a long term plan to consider allowing `.T` > to mean the same as `.mT`. > > > That sais, it is not correct to say there is any incompatibility! This > is an opinionated recommendation at most and if it was more it would > probably be a mistake there. > > - Sebastian > > > >> >> For non-2-dimensional arrays, the replacement for `arr.T` can be >> either: Array API compatible, namely `np.permute_dims(arr, >> range(arr.ndim)[::-1])`, or shorter, NumPy specific: >> `arr.transpose()`. >> >> The new discrepancy between `arr.T` and `arr.transpose()` is >> justified, as `T` is defined by the Array API, where `transpose` >> isn't and should retain the existing behavior. >> >> Please share your thoughts! >> >> Best regards, >> Mateusz >> _______________________________________________ >> NumPy-Discussion mailing list -- [email protected] >> To unsubscribe send an email to [email protected] >> https://mail.python.org/mailman3/lists/numpy-discussion.python.org/ >> Member address: [email protected] >> > > _______________________________________________ > NumPy-Discussion mailing list -- [email protected] > To unsubscribe send an email to [email protected] > https://mail.python.org/mailman3/lists/numpy-discussion.python.org/ > Member address: [email protected]
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