plot-locator-grid.py

# https://stackoverflow.com/questions/24943991/change-grid-interval-and-specify-tick-labels-in-matplotlib
import numpy as np
import matplotlib.pyplot as plt
from matplotlib.ticker import (AutoMinorLocator, MultipleLocator)

fig, ax = plt.subplots(figsize=(10, 8))

x = range(100+1)
y = range(100,200+1)
ax.plot(x, y, label="test")

# Set axis ranges; by default this will put major ticks every 25.
#ax.set_xlim(0, 200)
#ax.set_ylim(0, 200)

# Change major ticks to show every 20.
ax.xaxis.set_major_locator(MultipleLocator(20))
ax.yaxis.set_major_locator(MultipleLocator(20))

# Change minor ticks to show every 5. (20/4 = 5)
ax.xaxis.set_minor_locator(AutoMinorLocator(4))
ax.yaxis.set_minor_locator(AutoMinorLocator(4))

# Turn grid on for both major and minor ticks and style minor slightly
# differently.
ax.grid(which='major', color='#CCCCCC', linestyle='--')
ax.grid(which='minor', color='#CCCCCC', linestyle=':')

plt.show()