ColorScaleValidator should probably return a string when it's specified as a string.

[ivirshup]

Currently, color scale attributes have a kinda weird behavior:

import plotly.graph_objs as go
go.scatter.Marker(colorscale="Viridis").colorscale

(('V',), ('i',), ('r',), ('i',), ('d',), ('i',), ('s',))

This is unlike the behavior (to the best of my knowledge) for other attributes specified as strings:

go.scatter.Marker(color="red").color

'red'

And this is pretty unintuitive behavior when doing stuff like:

marker1 = go.scatter.Marker(colorscale="Viridis")
go.scatter.Marker(colorscale=marker1.colorscale)

ValueError: 
    Invalid value of type 'builtins.tuple' received for the 'colorscale' property of scatter.marker
        Received value: (('V',), ('i',), ('r',), ('i',), ('d',), ('i',), ('s',))

Though .update(marker1) does work for some reason.

My guess is all that needs to happen is to add an elif isinstance(v, str): return v to this function, since you won't be breaking that immutability requirement.

plotly.py/_plotly_utils/basevalidators.py

Lines 1276 to 1281 in d670bb0

	def present(self, v):
	# Return tuple of tuples so that colorscale is immutable
	if v is None:
	return None
	else:
	return tuple([tuple(e) for e in v])

[jonmmease]

Thanks for the report @ivirshup . Yeah, this is definitely an oversight. You're proposed fix should take care of it. Feel free to submit a PR, otherwise we'll get to in the next few weeks. Thanks!

[jonmmease]

Hi @ivirshup ,

I just pushed out release candidates for plotly.py 3.1.1 and plotlywidget 0.2.1. Installation instructions for the release candidates are at https://github.com/plotly/plotly.py/blob/bc1d4d188ab999cd9c21e3a7908729f156bc200f/README.md.

If you have a chance to confirm that this issue is resolved in the release candidate that would be awesome!