NdOverlay messing up legend item order

[openSourcerer9000]

Having the same issue as another user (#4082),

import numpy as np
import holoviews as hv
from collections import OrderedDict

hv.extension("plotly")
# hv.extension("bokeh")

data = OrderedDict(zip(['one','two','three','four','five'],
    [hv.Curve(np.random.rand(400)-i) for i in range(5)]))

hv.NdOverlay(data).opts(show_legend=True,width=1200)

with plotly backend:

bokeh backend:

It reorders to five, four, one, three, two for some reason, which for obvious reasons can make a plot confusing for a reader. Is there a workaround for this? Thanks

hv version 1.15.1

[openSourcerer9000]

So it looks like this is alphabetical order, is there a way to override this behavior?

[jbednar]

See holoviz/hvplot#551 ; it's a bit of a mess!

[openSourcerer9000]

I imagine there's just a sort or sort_values somewhere in the code that sorts legend items alphabetically, maybe this one. Finding it and removing it should solve the issue

holoviews/holoviews/core/data/pandas.py

Line 174 in 3afce15

column = column.sort_values()

[jbednar]

That's surely part of it, but different Elements apparently currently act differently (see examples in holoviz/hvplot#551), and Bokeh also does sorting. I think sorting is a useful thing to support as an option, but letting the user have complete control over the order is also important. I'm not sure how best to achieve that, and in any case we should document how it's achieved. PRs welcome!