Matplotlib.pyplot.axvspan() in Python

Matplotlib is a plotting library for creating static, animated, and interactive visualizations in Python.\ Pyplot is a Matplotlib module which provides a MATLAB-like interface. Matplotlib is designed to be as usable as MATLAB, with the ability to use Python and the advantage of being free and open-source.

matplotlib.pyplot.axvspan()

This function sets the vertical rectangle across the axes of the plot

Syntax: matplotlib.pyplot.axvspan(xmin, xmax, ymin=0, ymax=1, **kwargs)

Parameters:
xmin :Number indicating the starting position of the vertical rectangle on X-axis
xmin :Number indicating the ending position of the vertical rectangle on X-axis
ymin :vertical rectangle starting position on y axis, it will take values between 0 and 1, 0 being bottom of the axis, 1 being top of the axis
ymax :vertical rectangle ending position on y axis, it will take values between 0 and 1, 0 being bottom of the axis, 1 being top of the axis
**kwargs :Other optional parameters to change the properties of the rectangle, like changing color etc.

Example #1:

# Importing matplotlib.pyplot as plt
import matplotlib.pyplot as plt

# Initializing x and y
x =[1, 15, 27, 48, 50]
y =[1, 12, 22, 45, 67]

# Plotting the graph
plt.plot(x, y)

# Drawing rectangle starting
# x = 5 and extending till x = 20
# With vertical span starting at
# half the length of y-axis(ymin = 0.5)
# And extending till the top of
# axis(ymax = 1)
plt.axvspan(5, 20, ymin = 0.5, ymax = 1)
plt.show()

Output:

Example #2:

import matplotlib.pyplot as plt


x =[1, 15, 27, 48, 50]
y =[1, 12, 22, 45, 67]

plt.plot(x, y)

# Drawing rectangle starting
# x = 5 and extending till x = 15
# With vertical span starting at
# 25 % the length of y-axis
# And extending till the 80 % of
# axis And also we are setting
# the color of rectangle to yellow
# and its edge color to blue
plt.axvspan(5, 15, ymin = 0.25,
            ymax = 0.80, ec ='blue',
            color ='yellow')

plt.show()

Output :

Example #3:

import matplotlib.pyplot as plt


x =[1, 15, 27, 48, 50]
y =[1, 12, 22, 45, 67]

plt.plot(x, y)

# Setting alpha will make
# the rectangle transparent
plt.axvspan(10, 30, ymin = 0.15,
            ymax = 0.70, ec ='blue',
            color ='yellow',
            alpha = 0.5)

plt.show()

Output :