PYTHON

change tick labelsize matplotlib

import matplotlib.pyplot as plt
# We prepare the plot  
fig, ax = plt.subplots()

# We change the fontsize of minor ticks label 
ax.tick_params(axis='both', which='major', labelsize=10)
ax.tick_params(axis='both', which='minor', labelsize=8)

Matplotlib vertical tick labels

import matplotlib.pyplot as plt

x = range(6)
y = [-3, -2, -1, 1, 2, 3]
xlabels = [f'label {i}' for i in x]

fig, ax = plt.subplots()
ax.bar(x, y)

# ha='***' is not enough to visually align labels with ticks 
# use both ha='***' and rotation_mode='anchor'
ax.set_xticks(x, xlabels, rotation=45, ha='right', rotation_mode='anchor')

plt.show()