Can't hide colorbar/scale via marker layout attributes with plotly express figures

I tried to update the colorbar/colorscale via the marker attributes in update_traces (and also using a template), but none of the ones related to the colorbar has any effect:

import plotly.express as px

iris = px.data.iris()
fig = px.scatter(iris, 'sepal_width', 'sepal_length', 'sepal_length')
fig.update_traces(opacity=0.5, marker=dict(showscale=False, reversescale=True, cmin=6, size=20))

print(fig)

Figure({
    'data': [{'hoverlabel': {'namelength': 0},
              'hovertemplate': 'sepal_width=%{x}
sepal_length=%{marker.color}',
              'legendgroup': '',
              'marker': {'cmid': 0,
                         'color': array([5.1, 4.9, 4.7, 4.6, 5. , 5.4, 4.6, 5. , 4.4, 4.9, 5.4, 4.8, 4.8, 4.3,
                                         5.8, 5.7, 5.4, 5.1, 5.7, 5.1, 5.4, 5.1, 4.6, 5.1, 4.8, 5. , 5. , 5.2,
                                         5.2, 4.7, 4.8, 5.4, 5.2, 5.5, 4.9, 5. , 5.5, 4.9, 4.4, 5.1, 5. , 4.5,
                                         4.4, 5. , 5.1, 4.8, 5.1, 4.6, 5.3, 5. , 7. , 6.4, 6.9, 5.5, 6.5, 5.7,
                                         6.3, 4.9, 6.6, 5.2, 5. , 5.9, 6. , 6.1, 5.6, 6.7, 5.6, 5.8, 6.2, 5.6,
                                         5.9, 6.1, 6.3, 6.1, 6.4, 6.6, 6.8, 6.7, 6. , 5.7, 5.5, 5.5, 5.8, 6. ,
                                         5.4, 6. , 6.7, 6.3, 5.6, 5.5, 5.5, 6.1, 5.8, 5. , 5.6, 5.7, 5.7, 6.2,
                                         5.1, 5.7, 6.3, 5.8, 7.1, 6.3, 6.5, 7.6, 4.9, 7.3, 6.7, 7.2, 6.5, 6.4,
                                         6.8, 5.7, 5.8, 6.4, 6.5, 7.7, 7.7, 6. , 6.9, 5.6, 7.7, 6.3, 6.7, 7.2,
                                         6.2, 6.1, 6.4, 7.2, 7.4, 7.9, 6.4, 6.3, 6.1, 7.7, 6.3, 6.4, 6. , 6.9,
                                         6.7, 6.9, 5.8, 6.8, 6.7, 6.7, 6.3, 6.5, 6.2, 5.9]),
                         'coloraxis': 'coloraxis',
                         'reversescale': True,
                         'showscale': False,
                         'size': 20,
                         'symbol': 'circle'},
              'mode': 'markers',
              'name': '',
              'opacity': 0.5,
              'showlegend': False,
              'type': 'scatter',
              'x': array([3.5, 3. , 3.2, 3.1, 3.6, 3.9, 3.4, 3.4, 2.9, 3.1, 3.7, 3.4, 3. , 3. ,
                          4. , 4.4, 3.9, 3.5, 3.8, 3.8, 3.4, 3.7, 3.6, 3.3, 3.4, 3. , 3.4, 3.5,
                          3.4, 3.2, 3.1, 3.4, 4.1, 4.2, 3.1, 3.2, 3.5, 3.1, 3. , 3.4, 3.5, 2.3,
                          3.2, 3.5, 3.8, 3. , 3.8, 3.2, 3.7, 3.3, 3.2, 3.2, 3.1, 2.3, 2.8, 2.8,
                          3.3, 2.4, 2.9, 2.7, 2. , 3. , 2.2, 2.9, 2.9, 3.1, 3. , 2.7, 2.2, 2.5,
                          3.2, 2.8, 2.5, 2.8, 2.9, 3. , 2.8, 3. , 2.9, 2.6, 2.4, 2.4, 2.7, 2.7,
                          3. , 3.4, 3.1, 2.3, 3. , 2.5, 2.6, 3. , 2.6, 2.3, 2.7, 3. , 2.9, 2.9,
                          2.5, 2.8, 3.3, 2.7, 3. , 2.9, 3. , 3. , 2.5, 2.9, 2.5, 3.6, 3.2, 2.7,
                          3. , 2.5, 2.8, 3.2, 3. , 3.8, 2.6, 2.2, 3.2, 2.8, 2.8, 2.7, 3.3, 3.2,
                          2.8, 3. , 2.8, 3. , 2.8, 3.8, 2.8, 2.8, 2.6, 3. , 3.4, 3.1, 3. , 3.1,
                          3.1, 3.1, 2.7, 3.2, 3.3, 3. , 2.5, 3. , 3.4, 3. ]),
              'xaxis': 'x',
              'y': array([5.1, 4.9, 4.7, 4.6, 5. , 5.4, 4.6, 5. , 4.4, 4.9, 5.4, 4.8, 4.8, 4.3,
                          5.8, 5.7, 5.4, 5.1, 5.7, 5.1, 5.4, 5.1, 4.6, 5.1, 4.8, 5. , 5. , 5.2,
                          5.2, 4.7, 4.8, 5.4, 5.2, 5.5, 4.9, 5. , 5.5, 4.9, 4.4, 5.1, 5. , 4.5,
                          4.4, 5. , 5.1, 4.8, 5.1, 4.6, 5.3, 5. , 7. , 6.4, 6.9, 5.5, 6.5, 5.7,
                          6.3, 4.9, 6.6, 5.2, 5. , 5.9, 6. , 6.1, 5.6, 6.7, 5.6, 5.8, 6.2, 5.6,
                          5.9, 6.1, 6.3, 6.1, 6.4, 6.6, 6.8, 6.7, 6. , 5.7, 5.5, 5.5, 5.8, 6. ,
                          5.4, 6. , 6.7, 6.3, 5.6, 5.5, 5.5, 6.1, 5.8, 5. , 5.6, 5.7, 5.7, 6.2,
                          5.1, 5.7, 6.3, 5.8, 7.1, 6.3, 6.5, 7.6, 4.9, 7.3, 6.7, 7.2, 6.5, 6.4,
                          6.8, 5.7, 5.8, 6.4, 6.5, 7.7, 7.7, 6. , 6.9, 5.6, 7.7, 6.3, 6.7, 7.2,
                          6.2, 6.1, 6.4, 7.2, 7.4, 7.9, 6.4, 6.3, 6.1, 7.7, 6.3, 6.4, 6. , 6.9,
                          6.7, 6.9, 5.8, 6.8, 6.7, 6.7, 6.3, 6.5, 6.2, 5.9]),
              'yaxis': 'y'}],
    'layout': {'coloraxis': {'colorbar': {'title': {'text': 'sepal_length'}},
                             'colorscale': [[0.0, '#0d0887'], [0.1111111111111111,
                                            '#46039f'], [0.2222222222222222,
                                            '#7201a8'], [0.3333333333333333,
                                            '#9c179e'], [0.4444444444444444,
                                            '#bd3786'], [0.5555555555555556,
                                            '#d8576b'], [0.6666666666666666,
                                            '#ed7953'], [0.7777777777777778,
                                            '#fb9f3a'], [0.8888888888888888,
                                            '#fdca26'], [1.0, '#f0f921']]},
               'height': 600,
               'legend': {'tracegroupgap': 0},
               'margin': {'t': 60},
               'template': '...',
               'xaxis': {'anchor': 'y', 'domain': [0.0, 0.98], 'title': {'text': 'sepal_width'}},
               'yaxis': {'anchor': 'x', 'domain': [0.0, 1.0], 'title': {'text': 'sepal_length'}}}
})

When I try the same thing with a figure created without plotly express, it works as expected (note that I change between True and False in this example, just to show that all colorbar marker attributes work as expected):

import plotly.graph_objects as go
import numpy as np

fig = go.Figure(data=go.Scatter(
    y = np.random.randn(500),
    mode='markers',
    marker=dict(
        size=16,
        color=np.random.randn(500), #set color equal to a variable
        colorscale='Viridis', # one of plotly colorscales
        showscale=False,
    )
))

fig.update_traces(opacity=0.5, marker=dict(showscale=True, reversescale=True, cmid=0, size=20))

print(fig)

Figure({
    'data': [{'marker': {'cmid': 0,
                         'color': array([-0.58207535,  0.79725625, -1.54958717, ...,  0.01890008,  1.49074695,
                                          1.6721    ]),
                         'colorscale': [[0.0, '#440154'], [0.1111111111111111,
                                        '#482878'], [0.2222222222222222,
                                        '#3e4989'], [0.3333333333333333,
                                        '#31688e'], [0.4444444444444444,
                                        '#26828e'], [0.5555555555555556,
                                        '#1f9e89'], [0.6666666666666666,
                                        '#35b779'], [0.7777777777777778,
                                        '#6ece58'], [0.8888888888888888,
                                        '#b5de2b'], [1.0, '#fde725']],
                         'reversescale': True,
                         'showscale': True,
                         'size': 20},
              'mode': 'markers',
              'opacity': 0.5,
              'type': 'scatter',
              'y': array([-0.29207826,  1.35449056, -0.52644856, ..., -0.90899513,  1.79810226,
                           0.06748418])}],
    'layout': {'template': '...'}
})

Viewing the printed figure dicts shows that there is a coloraxis attribute created with plotly express, not sure if that is what makes the axis impossible to hide or if I am just using the wrong approach here.

[aheze]

In v5.1.0, this works for me:

fig.update_coloraxes(showscale=False)

Before	After

[nicolaskruchten]

Indeed, Plotly Express doesn’t define its colorbar per-trace but rather figure-wide using layout.coloraxis. You can control this colorbar’s configuration via layout.coloraxis.colorbar attributes. You can control whether or not this colorbar is shown via layout.coloraxis.showscale.