Plotly scatterplot legends not displaying legend title, but with = sign for each color

Question

Plotly refuses to display the legend like it should. In my case, the color is dictated by a datapoint's "Name". The Legend displays Name=[name of the datapoint] instead of giving the Legend the title "Name".

It looks like the image above, but it should look like this:

Like the "species" title, the title "Name" should be displayed in my case. Any help?

Answer 1

It's hard to tell exactly what's happening here without a reproducible example. To my knowledge, a proper application of px.scatter shouldn't render the result you're displaying. At least not for newer versions of Plotly. But in either case, and for full flexibility, you can run the two following lines to insert a legend title, and display only the text for each legend element that appears after the '=':

fig.for_each_trace(lambda t: t.update(name=t.name.split("=")[-1]))
fig.update_layout(legend_title_text = '<b>your title</b>')

Plot 1 - Before corrections:

Plot 2 - After corrections:

Complete code:

import plotly.graph_objects as go
import plotly.express as px

# data
df = px.data.iris()

# adjust data to reproduce the problem
df['species'] = ['species=' + s for s in df['species']]

# build figure
fig = px.scatter(df, x='petal_length', y = 'petal_width', color = 'species')

# change legend entries
fig.for_each_trace(lambda t: t.update(name=t.name.split("=")[-1]))

# edit title and show figure
fig.update_layout(legend_title_text = '<b>Custom title</b>')
fig.show()