在 matplotlib 中旋转第二个 y 轴刻度标签

Question

I need to rotate the 2nd y-axis ticklabel and add a label for this axis as well in the figure below

import matplotlib.pyplot as plt
import matplotlib.lines as mlines
import matplotlib.transforms as mtransforms

fig, ax1 = plt.subplots(constrained_layout=True)
x = [61,62,62,59,62,59,62,63,61,60,103,104,109,105,109,105,109,111,110,107]
y = [62,62,62,62,60,60,62,62,62,63,106,107,106,106,105,105,105,106,107,108]
ax1.plot(x,y,'b.')
x2 = [2.2,3.4,4.3,5.1,5.5,5.7]
y2 = [2.3,2.8,3.2,3.9,4.5,5.9]
ax2 = ax1.twinx().twiny()
ax2.tick_params(axis="y",labelrotation=90,direction='out',length=6, width=2, colors='r',grid_color='r', grid_alpha=0.5) #called tick_params before the plot and didn't work
ax2.plot(x2,y2,'r.')
ax2.set_xlim(0,10)
ax2.set_ylim(0,10)
ax2.set_yticklabels(['Label1', 'Label2', 'Label3'], rotation=90) #y ticklabels is not rotating
ax2.set_xlabel('abc', rotation=0, fontsize=20, labelpad=20)
ax2.set_ylabel('abc', rotation=0, fontsize=20, labelpad=20)   #y label is not wroking

plt.yticks(rotation=90)

line = mlines.Line2D([0, 1], [0, 1], color='red')
transform = ax2.transAxes
line.set_transform(transform)
ax2.add_line(line)
plt.show()

This code produced the figure below

The problem is ax2.set_yticklabels and ax2.set_ylabel don't work.

I want to add a label to 2nd y-axis and rotate the tick label for that axis. Also, how to control the position of the tick mark at these axes, I want it to be at the same position of tick marks of 1st y-axis and 1st x-axis. So Label1 will shift up and 0 will shift right

Thanks

Answer 1

When you are instancing ax2 = ax1.twinx().twiny() , you can no longer modify the y axis. Instead, create two axes and modify accordingly. Modified code and the result is below.

import matplotlib.pyplot as plt
import matplotlib.lines as mlines
import matplotlib.transforms as mtransforms

fig, ax1 = plt.subplots(constrained_layout=True)
x = [61,62,62,59,62,59,62,63,61,60,103,104,109,105,109,105,109,111,110,107]
y = [62,62,62,62,60,60,62,62,62,63,106,107,106,106,105,105,105,106,107,108]
ax1.plot(x,y,'b.')
x2 = [2.2,3.4,4.3,5.1,5.5,5.7]
y2 = [2.3,2.8,3.2,3.9,4.5,5.9]
ax2 = ax1.twinx()  # ax2 handles y
ax3 = ax2.twiny()  # ax3 handles x
ax3.plot(x2,y2,'r.')
ax3.set_xlim(0,10)
ax2.set_ylim(0,10)
ax3.set_xlabel('abc', rotation=0, fontsize=20, labelpad=20)
ax2.set_ylabel('abc', rotation=0, fontsize=20, labelpad=20)   
ax2.tick_params(axis="y",labelrotation=90,direction='out',length=6, width=2, colors='r',grid_color='r', grid_alpha=0.5)
ax2.set_yticklabels(['Label1', 'Label2', 'Label3'], rotation=-90)     
plt.yticks(rotation=90)
line = mlines.Line2D([0, 1], [0, 1], color='red')
transform = ax2.transAxes
line.set_transform(transform)
ax2.add_line(line)
plt.show()

The resulting graph has all the y label/tick modifications.