Make logically shading region for a curve in matplotlib

To make logically shading region for a curve in matplotlib, we can take the following steps

Steps

Set the figure size and adjust the padding between and around the subplots.
Create t, s1 and s2 data points using numpy.
Create a figure and a set of subplots.
Plot t and s1 data points; add a horizontal line across the axis.
Create a collection of horizontal bars spanning *yrange* with a sequence of xranges.
Add a '~.Collection' to the axes' collections; return the collection.
To display the figure, use Show() method.

Example

import numpy as np
import matplotlib.pyplot as plt
import matplotlib.collections as collections

plt.rcParams["figure.figsize"] = [7.00, 3.50]
plt.rcParams["figure.autolayout"] = True

t = np.arange(0.0, 2, 0.01)
s1 = np.sin(2 * np.pi * t)
s2 = 1.2 * np.sin(4 * np.pi * t)

fig, ax = plt.subplots()

ax.plot(t, s1, color='black')
ax.axhline(0, color='black', lw=2)

collection = collections.BrokenBarHCollection.span_where(t, ymin=0, ymax=1,
   where=s1 > 0, facecolor='green', alpha=0.5
)
ax.add_collection(collection)

collection = collections.BrokenBarHCollection.span_where( t, ymin=-1, ymax=0,
   where=s1 < 0, facecolor='red', alpha=0.5
)
ax.add_collection(collection)

plt.show()

Output

It will produce the following output −

Rishikesh Kumar Rishi

Updated on: 19-Oct-2021

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