Displaying a chart label for single line chart

📊 Plotly Python
1

Hello,

I’m trying to display a line chart with one line, and I’d like for that chart to display a label / legend for that line the same way it would if there were multiple lines.

Here’s a quick example:

CHART WITH LABELS

import pandas as pd
import numpy as np
import plotly.graph_objects as go

dates = pd.date_range(start='2020-01-01', periods=100)
random = np.random.RandomState(0)
random2 = np.random.RandomState(1)

data1  = random.random(100)
data2  = random2.random(100)

a_values = ['A' for i in range(100)]
b_values = ['B' for i in range(100)]

df1 = pd.DataFrame({
  'data': data1,
  'value': a_values
}, index=dates)

df2 = pd.DataFrame({
  'data': data2,
  'value': b_values
}, index=dates)

df = pd.concat([df1, df2])

fig = go.Figure()
fig.add_trace(go.Scatter(x=df.index, y=df[df.value == 'A']['data'], name='Label 1'))
fig.add_trace(go.Scatter(x=df.index, y=df[df.value == 'B']['data'], name='Label 2'))
fig.show()

This will yield the following chart:

sample_chart
sample_chart1516×643 99.9 KB

My issue is that I’d like the same types of labels to appear in the legend even if there’s one line.

If I re-create the same chart but with only one line I’ll get the following:

CHART WITHOUT LABELS

fig = go.Figure()
fig.add_trace(go.Scatter(x=df.index, y=df[df.value == 'A']['data'], name='Label 1'))
fig.show()

sample_chart2
sample_chart21368×632 67.2 KB

What can I do to get the value ‘Label 1’ to appear on the legend on the right hand side?