ENH add vlines_ attribute to PDP Display to hide deciles

[NicolasHug]

I added a vlines_ attribute to the PDP Display so that we can hide the deciles vertical lines. But maybe there's a way to access the lines via the ax? I couldn't find anything.

@thomasjpfan please LMK if it's worth it, and I'll add test or close

[thomasjpfan]

There is a way to access everything through ax. Since anyone can draw lines onto the axes, having the artist in the display object specifics which lines were draw by the display object.

I think adding vlines is a good idea.

[thomasjpfan]

To keep with the style of the surrounding code:

self.vlines_ = np.empty_like(self.axes_)
vlines_ravel = self.vlines_.ravel(order='C')

(Yes the order is C by default, but I recall a comment wanting this to be explicit)

[thomasjpfan]

Given #15788, we should specific the dtype as object as well.

[NicolasHug]

OK I'll make it explicit, though note thatempty_like will explicitly set the dtype to that of axes_

[NicolasHug]

Thanks for the feedback. ready for actual reviews now. I also realized we would need a hlines attribute for 2-way PDPs

[thomasjpfan]

LGTM! Needs whats new in 0.23

[NicolasHug]

Easy one @rth if you have time?

[rth]

Sounds good. Could you point me to an example of PDP plot with deciles that we would be hiding?

[NicolasHug]

here you have plots with deciles https://scikit-learn.org/stable/modules/partial_dependence.html which are the black vertical bars on the 1-way plots and the the 2-way plot also has horizontal bars

here is an example without deciles (first plot) http://nicolas-hug.com/blog/pdps

[rth]

which are the black vertical bars on the 1-way plots and the the 2-way plot also has horizontal bars

The ticks on the axis, right? I guess you can always change ax.xaxis.set_ticks but indeed I don't know how to remove some and not the others.

[rth]

Ahh, I didn't get that you are drawing them manually, so they are not part of the ax.xaxis / ax.yaxis objects.

LGTM.

[NicolasHug]

thanks!