Overlay Shaded Regions on a Line Plot Based on Conditions

Question

I would like to plot a line plot and make different overlay based on condition as illustrated below.

May I know how, or if possible, please kindly redirect me to right material on achieving the intended objective.

import numpy as np
import pandas as pd
import seaborn as sns
import matplotlib.pyplot as plt
np.random.seed(0)
rng = np.random.default_rng(2)
mlist=[]
for _ in range(4):

    m=np.random.rand(4).tolist()
    n=rng.integers(0, 6, size=(1)).tolist()*4
    df = pd.DataFrame(zip(m,n), columns=['yval','type'])
    mlist.append(df)

df=pd.concat(mlist).reset_index(drop=True).reset_index()
sns.lineplot(data=df, x="index", y="yval")
plt.show()

Suggestion using Matplotlib or Seaborn, or any other package are welcome

Answer 1

The filling of the section was achieved using axvspan. I also used text for annotations.

The line is plotted with sns.lineplot, but can also be implemented with either of the following:

• ax = df.plot(y='yval')
• fig, ax = plt.subplots() and ax.plot('index', 'yval', data=df)

import numpy as np
import pandas as pd
import seaborn as sns
import matplotlib.pyplot as plt

# Create Sample Data
np.random.seed(0)
rng = np.random.default_rng(2)

m = np.random.rand(16)
n = np.repeat(rng.integers(0, 6, size=4), 4)
df = pd.DataFrame({'index': range(len(m)), 'yval': m, 'type': n})

# Plot the line
ax = sns.lineplot(data=df, x="index", y="yval")

# Add the overlay spans and annotations
overlay = {0: 'm', 1: 'gray', 5: 'r'}

for i in np.arange(0, len(df), 4):
    tmp = df.iloc[i:i+4, :]
    v = overlay.get(tmp.type.unique()[0])
    ax.axvspan(min(tmp.index), max(tmp.index)+1, color=v, alpha=0.3)
    ax.text(((min(tmp.index)+max(tmp.index)+1) / 2)-1, 0.1, f'type {tmp.type.unique()[0]}', fontsize=12)

plt.show()