How to avoid duplicate legend labels in plotly or pass custom legend labels

Question

How can I avoid duplicate legend labels in subplots? One way I would go about it in matplotlib would be to pass custom legend labels to an legend object. I couldn\'t find an

Answer 1

This is a code snippet I came up with which avoids to set showlegend=False manually on each trace with a duplicate name.

names = set()
fig.for_each_trace(
    lambda trace:
        trace.update(showlegend=False)
        if (trace.name in names) else names.add(trace.name))

fig.for_each_trace calls the passed function for each trace. The function keeps track of which legend names already occurred (via the set names, like @LucG proposed in a comment), and hides legend entries for duplicate (or triplicate, ...) names.

The code needs to be run after all traces have been added to the figure, and before it is shown.