[Numpy-discussion] Re: NEP 51: Changing the Representation of NumPy Scalars

I like this. NumPy scalar printing is confusing to new users, who might think they are Python scalars. And even if you understand them, it's always been annoying that you have to do further introspection to see the dtype. I also like the longdouble change (the name float128 has misled me in the past), and the decision to make everything copy-paste round-trippable. Are there also plans to add "np." to array() and the string forms of other objects? Aaron Meurer On Fri, Oct 28, 2022 at 2:55 AM Sebastian Berg wrote:

Hi all,

As mentioned earlier, I would like to propose changing the representation of scalars in NumPy. Discussion and ideas on changes are much appreciated!

The main change is to show scalars as:

* `np.float64(3.0)` ­instead of just `3.0` * `np.True_` instead of `True` * `np.void((3, 5), dtype=[('a', '

This way it is clear for users that they are dealing with NumPy scalars which behave different from Python scalars. The `str()` that is given when using `print()` and the way arrays are shown will be unchanged.

The NEP draft can be found here:

https://numpy.org/neps/nep-0051-scalar-representation.html

and it includes more details and related changes.

The implementation is largely finished and can be found here:

https://github.com/numpy/numpy/pull/22449

W are fairly late in the release cycle and the change should not block other things. So, the aim is to merge it early in the next release cycle. That way downstream has time to fix documentation is wanted.

Depending on how discussion goes, I hope to formally propose the NEP fairly soon, so that the merging the implementation doesn't need to wait on NEP approval.

Cheers,

Sebastian

On Thu, 2022-09-08 at 11:38 +0200, Sebastian Berg wrote:

...

TL;DR: NumPy scalars representation is e.g. `34.3` instead of `float32(34.3)`. So the representation is missing the type information. What are your thoughts on changing that?

Hi all,

I am thinking about the next steps for NEP 50 (The NEP wants to fix the NumPy promotion rules, especially with respect to scalars):

https://numpy.org/neps/nep-0050-scalar-promotion.html

In relation to that, there was one point that Stéfan brought up previously.

The NumPy scalars (representation) currently print as numbers:

>>> np.float32(34.3) 34.3 >>> np.uint8(5) 5

That can already be confusing now. However, it gets more problematic if NEP 50 is introduced since the behavior between a Python `34.3` and `np.float32(34.3)` would differ more than it does now (please refer to the NEP).

The change would be that we should print as:

float64(34.3) (or similar?)

This Email is mainly to ask for any feedback or concern on such a change. I suspect we may have to write a very brief NEP about it.

If there is little concern, maybe we could move forward such a change promptly. Otherwise it could be moved forward together with NEP 50 and take effect in a "major" release [1].

Cheers,

Sebastian

[1] Note that for me, even a major release would hopefully not affect the majority of users or be very disruptive.

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