How to add multiple vertical rectangles to a single chart in plotly?

Question

I'm struggling to figure out how to create multiple rectangles that span entire plots using plotly.

I've done this with matplotlib using axvspan():

for month in recession:
plt.axvspan(month, month + pd.offsets.MonthEnd(0), color="red", alpha=0.1)

I'm assuming this is possible using add_vrect()?

Below is the code along with a sample data set that I want to add the vertical rectangles to with the hope of spanning all of the dates corresponding with the Recession periods. Any help would be greatly appreciated.

import pandas as pd
import plotly.graph_objects as go
import datetime

# Load data
history = pd.read_csv("sample_data.csv")
history["Date"] = pd.to_datetime(history["Date"], format="%Y-%m-%d")
history.set_index("Date", inplace=True)

# Filter out recession dates
recession = history.loc[history["Regime"] == "Recession"].index

# Plot Dow Jones average against time
fig = go.Figure()
fig.add_trace(go.Scatter(x=history.index, y=history["DJI"], mode="lines"))

# Show plot
fig.show()

Sample Data

Date	Regime	DJI
1907-01-01	Normal	68.33
1907-02-01	Normal	66.41
1907-03-01	Normal	65.57
1907-04-01	Recession	58.05
1907-05-01	Recession	61.05
1907-06-01	Recession	56.56
1907-07-01	Recession	57.94
1907-08-01	Normal	62.35
1907-09-01	Normal	63.01
1907-10-01	Normal	63.29
1907-11-01	Normal	62.99
1907-12-01	Normal	63.17
1908-01-01	Normal	63.28
1908-02-01	Normal	63.41
1908-03-01	Normal	63.83
1908-04-01	Normal	63.11
1908-05-01	Recession	59.26
1908-06-01	Recession	58.99
1908-07-01	Recession	58.37
1908-08-01	Recession	58.01
1908-09-01	Recession	57.66
1908-10-01	Recession	57.23
1908-11-01	Recession	56.84
1908-12-01	Recession	56.76
1909-01-01	Recession	56.24
1909-02-01	Recession	57.15
1909-03-01	Recession	57.89
1909-04-01	Normal	61.01
1909-05-01	Normal	61.34
1909-06-01	Normal	61.92
1909-07-01	Normal	62.39
1909-08-01	Normal	63.01
1909-09-01	Normal	63.22
1909-10-01	Normal	63.89
1909-11-01	Normal	64.21
1909-12-01	Normal	64.88

Answer 1

I don't have much experience using Plotly, but I think the issue is that you're trying to use Plotly to create part of the figure and matplotlib to create the other. Instead, you can do it all in matplotlib.

import pandas as pd
import matplotlib.pyplot as plt

plt.close("all")

# Load data
history = pd.read_csv("sample_data.csv")
history["Date"] = pd.to_datetime(history["Date"], format="%Y-%m-%d")
history.set_index("Date", inplace=True)

# Filter out recession dates
recession = history.loc[history["Regime"] == "Recession"].index

fig, ax = plt.subplots()
for month in recession:
    plt.axvspan(month, month + pd.offsets.MonthEnd(0), color="grey", alpha=0.5)
ax.plot(history.index, history.DJI, "-.")
ax.tick_params(axis="x", rotation=45)
ax.set_xlabel("Date")
ax.set_ylabel("DJI")
ax.set_title("DJI Over Time")
fig.tight_layout()

The vertical bands are from the start of one month and end of the other overlapping slightly. I leave it to you to figure out how to find the ranges of each recession and plot the gray band from the start to the end.