如何使用matplotlib制作第二个垂直轴，左侧带有标签？

Question

I was trying to make a graph with two secondary vertical axis (y-axis), with python matplotlib.

I was using twinx() method, where one of the two new axis is with the default behavior (labels on the right) and the other with labels on the left , like the example of tan(x) on the figure bellow (created in an specific software).

Is there an easy way to do that? I'm not restricted to use the twinx() method, if there is another way

Answer 1

Here is a way to add two secondary y-axis, one towards the inside:

import numpy as np
import matplotlib.pyplot as plt

x = np.linspace(.5, 10, 1000)
y1 = np.cos(x)
y2 = np.sin(2 * x)
y3 = np.clip(np.tan(x * .6), -75, 75)

fig, ax1 = plt.subplots()

color = 'dodgerblue'
ax1.set_ylabel('$cos(x)$', color=color)
ax1.plot(x, y1, color=color)
ax1.tick_params(axis='y', labelcolor=color)

ax2 = ax1.twinx()
color = 'limegreen'
ax2.set_ylabel('$sin(2 x)$', color=color)
ax2.plot(x, y2, color=color)
ax2.tick_params(axis="y", labelcolor=color)

ax3 = ax1.twinx()
color = 'crimson'
ax3.set_ylabel('$tan(.6 x)$', color=color, labelpad=-40)
ax3.plot(x, y3, color=color)
ax3.tick_params(axis="y", labelcolor=color, direction="in", pad=-5)
plt.setp(ax3.get_yticklabels(), ha="right")

ax1.set_xlim(0, 12)

fig.tight_layout()
plt.show()