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How to add vertical line to legends, created via add_vline method in plotly python

Using Python 3.8, Plotly 4.13.

Within my scatterplot, I've added multiple vertical lines using add_vline() method in plotly. However I cannot add it to legend allowing me to turn on/off vertical lines.

How can add vertical lines to the legend?

Here is example of how I've created my plot:

fig = go.Figure()

fig.add_trace(
    go.Scatter(name="name added to legend", datas...)
)

for dt in dates:
    fig.add_vline(x=dt, line_width=1, etc...)

outputting something like this:

enter image description here

all plots created using go.Scatter are added to legend however not vertical lines created by fig.add_vline.

Solution

  • The vertical line is just a decoration of the graph, not a graph object, so it is not included in the legend. So if you want to use the ON/OFF function in the legend, you can add a new one in go.Scatter and use it for the function to select in the legend. I modified the example from the official reference to create the code.

    import plotly.express as px
import plotly.graph_objects as go
df = px.data.stocks()
dmax = df[['GOOG', 'AAPL', 'AMZN', 'FB', 'NFLX', 'MSFT']].values.max()
dmin = df[['GOOG', 'AAPL', 'AMZN', 'FB', 'NFLX', 'MSFT']].values.min()
fig = go.Figure()

fig.add_trace(go.Scatter(x=df.date, y=df['AAPL'], mode='lines', name='AAPL'))
fig.add_trace(go.Scatter(x=df.date, y=df['GOOG'], mode='lines', name='GOOG'))
fig.add_trace(go.Scatter(x=[df.date[10],df.date[10]], 
                         y=[dmin,dmax], 
                         mode='lines', 
                         line=dict(color='green', width=2, dash='dash'),
                         name='2018-03-12'))

fig.show()

    enter image description here