horizontal line with matplotlib code example

Example 1: vertical line in matplotlib

xposition = [0.3, 0.4, 0.45]
for xc in xposition:
    plt.axvline(x=xc, color='k', linestyle='--')

Example 2: how to plotting horizontal bar on matplotlib

import matplotlib.pyplot as plt 

data = [5., 25., 50., 20.]
plt.barh(range(len(data)), data)
plt.show()