how to change x axis label in matplotlib code example

Example 1: add x axis label python

plt.xlabel("X axis label")

Example 2: changing axis labels matplotlib

import matplotlib.pyplot as plt

fig, ax = plt.subplots()

labels = [item.get_text() for item in ax.get_xticklabels()]
labels[1] = 'Testing'

ax.set_xticklabels(labels)