Change x tick labels in pyplot

change_x_tick_labels.py

 # https://stackoverflow.com/a/11250884/776348

import matplotlib.pyplot as plt

fig, ax = plt.subplots()

# We need to draw the canvas, otherwise the labels won't be positioned and 
# won't have values yet.
fig.canvas.draw()
labels = ['m','y','l','a','b','e','l','s']


for label in ax.xaxis.get_ticklabels():
    # tick.label.set_fontsize(19) 
    # specify integer or one of preset strings, e.g.
    label.set_fontsize('x-small') # tick label attributes  
    label.set_rotation('vertical')
    
ax.set_xticklabels(labels) # tick label content

plt.xticks(range(len(labels))) # tick positions to make sure you get them printed in right frequency

plt.show()