Twin Axes

fig, ax1 = plt.subplots()

x = arange(1,7,0.1)

ax1.plot(x, 2 * np.pi * x, lw=2, color="blue")

ax1.set_ylabel(r"Circumference $(cm)$", fontsize=16, color="blue")

for label in ax1.get_yticklabels():

label.set_color("blue")

ax2 = ax1.twinx()

ax2.plot(x, np.pi * x ** 2, lw=2, color="darkgreen")

ax2.set_ylabel(r"area $(cm^2)$", fontsize=16, color="darkgreen")

for label in ax2.get_yticklabels():

label.set_color("darkgreen")