Error in plotly express scatter with continuous_color_scale and marginal_x

[chk2817]

Hello

i am logging this as i think this might be a bug. I found while building a Dash app but the same issue arises in a a jupyter notebook.

import plotly.express as px
df = px.data.iris()

below, it works as expected:

fig = px.scatter(df, x="sepal_width", y="sepal_length", color="sepal_length",color_continuous_scale='Viridis')
fig

so is the following

fig = px.scatter(df, x="sepal_width", y="sepal_length", color="sepal_length",marginal_x='box')
fig

But the following expression breaks down

fig = px.scatter(df, x="sepal_width", y="sepal_length", color="sepal_length",marginal_x='box',color_continuous_scale='Viridis')
fig

it looks like box marker is using 'V' of Viridis in the color_continuous_scale.

Thanks

[chk2817]

So to make it work, using the string name is not working, need to pass the corresponding actual list of colors like color_continuous_scale=px.colors.sequential.Viridis
a bit of a problem (though may be due to my inexperience on this).
for my dash playground app, where user can select a color scheme, i managed to find a 'detour' using the following ex:

sequential_swatch=['Brwnyl', 'Agsunset', etc..., 'Viridis', 'Plotly3']
sequential_swatch_dict={x:getattr(px.colors.sequential,x) for x in sequential_swatch}

and in the callback to update the plot, i use for ex:

fig=px.scatter(...., color_continuous_scale=swatches_dict['Viridis']...)

where 'Viridis' can be any other color scheme selection from sequential, diverging etc...

[nicolaskruchten]

Thanks for reporting this problem! Definitely a bug that was introduced when we started accepting string names and lists of lists as color scales instead of just lists of colors. We'll try to get a fix into the next version.

[wbeardall]

This is still an issue as of 5.12.0.

Minimal reproducible example is provided below.

import plotly

print(plotly.__version__)

import plotly.express as px

# Create the scatter plot with continuous color scale
fig = px.scatter(px.data.iris(), x="sepal_width", y="sepal_length", color="petal_length",
                 marginal_x="histogram",
                 color_continuous_scale='magma')

fig.show()

Edited traceback is given below:

5.12.0
Traceback (most recent call last):
  File "/dummy.py", line 8, in <module>
    fig = px.scatter(px.data.iris(), x="sepal_width", y="sepal_length", color="petal_length",
  File "/opt/conda/lib/python3.8/site-packages/plotly/express/_chart_types.py", line 66, in scatter
    return make_figure(args=locals(), constructor=go.Scatter)
  File "/opt/conda/lib/python3.8/site-packages/plotly/express/_core.py", line 2171, in make_figure
    trace.update(patch)
  File "/opt/conda/lib/python3.8/site-packages/plotly/basedatatypes.py", line 5116, in update
    BaseFigure._perform_update(self, dict1, overwrite=overwrite)
  File "/opt/conda/lib/python3.8/site-packages/plotly/basedatatypes.py", line 3900, in _perform_update
    BaseFigure._perform_update(plotly_obj[key], val)
  File "/opt/conda/lib/python3.8/site-packages/plotly/basedatatypes.py", line 3921, in _perform_update
    plotly_obj[key] = val
  File "/opt/conda/lib/python3.8/site-packages/plotly/basedatatypes.py", line 4851, in __setitem__
    self._set_prop(prop, value)
  File "/opt/conda/lib/python3.8/site-packages/plotly/basedatatypes.py", line 5195, in _set_prop
    raise err
  File "/opt/conda/lib/python3.8/site-packages/plotly/basedatatypes.py", line 5190, in _set_prop
    val = validator.validate_coerce(val)
  File "/opt/conda/lib/python3.8/site-packages/_plotly_utils/basevalidators.py", line 1375, in validate_coerce
    self.raise_invalid_val(v)
  File "/opt/conda/lib/python3.8/site-packages/_plotly_utils/basevalidators.py", line 288, in raise_invalid_val
    raise ValueError(
ValueError: 
    Invalid value of type 'builtins.str' received for the 'color' property of histogram.marker
        Received value: 'm'

    The 'color' property is a color and may be specified as:
      - A hex string (e.g. '#ff0000')
      - An rgb/rgba string (e.g. 'rgb(255,0,0)')
      - An hsl/hsla string (e.g. 'hsl(0,100%,50%)')
      - An hsv/hsva string (e.g. 'hsv(0,100%,100%)')
      - A named CSS color:
            aliceblue, antiquewhite, aqua, aquamarine, azure,
            beige, bisque, black, blanchedalmond, blue,
            blueviolet, brown, burlywood, cadetblue,
            chartreuse, chocolate, coral, cornflowerblue,
            cornsilk, crimson, cyan, darkblue, darkcyan,
            darkgoldenrod, darkgray, darkgrey, darkgreen,
            darkkhaki, darkmagenta, darkolivegreen, darkorange,
            darkorchid, darkred, darksalmon, darkseagreen,
            darkslateblue, darkslategray, darkslategrey,
            darkturquoise, darkviolet, deeppink, deepskyblue,
            dimgray, dimgrey, dodgerblue, firebrick,
            floralwhite, forestgreen, fuchsia, gainsboro,
            ghostwhite, gold, goldenrod, gray, grey, green,
            greenyellow, honeydew, hotpink, indianred, indigo,
            ivory, khaki, lavender, lavenderblush, lawngreen,
            lemonchiffon, lightblue, lightcoral, lightcyan,
            lightgoldenrodyellow, lightgray, lightgrey,
            lightgreen, lightpink, lightsalmon, lightseagreen,
            lightskyblue, lightslategray, lightslategrey,
            lightsteelblue, lightyellow, lime, limegreen,
            linen, magenta, maroon, mediumaquamarine,
            mediumblue, mediumorchid, mediumpurple,
            mediumseagreen, mediumslateblue, mediumspringgreen,
            mediumturquoise, mediumvioletred, midnightblue,
            mintcream, mistyrose, moccasin, navajowhite, navy,
            oldlace, olive, olivedrab, orange, orangered,
            orchid, palegoldenrod, palegreen, paleturquoise,
            palevioletred, papayawhip, peachpuff, peru, pink,
            plum, powderblue, purple, red, rosybrown,
            royalblue, rebeccapurple, saddlebrown, salmon,
            sandybrown, seagreen, seashell, sienna, silver,
            skyblue, slateblue, slategray, slategrey, snow,
            springgreen, steelblue, tan, teal, thistle, tomato,
            turquoise, violet, wheat, white, whitesmoke,
            yellow, yellowgreen
      - A number that will be interpreted as a color
        according to histogram.marker.colorscale
      - A list or array of any of the above