import numpy as np
import matplotlib.pyplot as plt

# Generate some data
X = np.linspace(-10, 10, 1000)
Y = np.sin(X)**2

# Specify markers
markers = ['o', 'v', '^', '<', '>']

def markevery(i):
    # I tried a *lot* of values here, none were working for the 4 plots
    return (i / 50., 0.1)

plt.figure()

# First plot in normal plot
plt.subplot(221)
for i in range(10):
    plt.plot(X, Y + i / 10., marker=markers[i % len(markers)], markevery=markevery(i), label=str(i))
plt.legend()
plt.title("plt.plot(): markers are here!")

# Then plot in semilogx
plt.subplot(222)
for i in range(10):
    plt.semilogx(X, Y + i / 10., marker=markers[i % len(markers)], markevery=markevery(i), label=str(i))
plt.legend()
plt.title("plt.semilogx(): markers are NOT here!")

# And then semilogy
plt.subplot(223)
for i in range(10):
    plt.semilogy(X, Y + i / 10., marker=markers[i % len(markers)], markevery=markevery(i), label=str(i))
plt.legend()
plt.title("plt.semilogy(): markers are here!")

# Finally plot in loglog
plt.subplot(224)
for i in range(10):
    plt.loglog(X, Y + i / 10., marker=markers[i % len(markers)], markevery=markevery(i), label=str(i))
plt.legend()
plt.title("plt.loglog(): markers are NOT here!")

plt.suptitle("Weird behavior of markevery between plt.plot, plt.semilogx, plt.semilogy, plt.loglog")
plt.show()