旋转x轴文本并将y标签移动到轴的顶部（多个y轴）

Question

In the following python code I'm plotting time datas and multiple y-values out of a dataframe. Now I want to: - rotate the time values of the x-axis vertically - move all y-labels (y1-y4) to the top of the axis Does anyone have suggestions or solutions ?

import pandas as pd
from mpl_toolkits.axes_grid1 import host_subplot
import mpl_toolkits.axisartist as AA
import matplotlib.pyplot as plt

data = {'time':['00:00:00','18:00:00','23:59:00'],
          'y1': [1,2,3],'y2': [4,5,6],'y3': [7,8,9],'y4': [10,11,12]}

df=pd.DataFrame(data,columns=['time','y1','y2','y3','y4'])
df['time']=pd.to_datetime(df['time'],format='%H:%M:%S')

host=host_subplot(111,axes_class=AA.Axes)
plt.subplots_adjust(right=0.75)
par1=host.twinx()
par2=host.twinx()
par3=host.twinx()
offset1=40
offset2=80 
new_fixed_axis=par2.get_grid_helper().new_fixed_axis

par2.axis['right']=new_fixed_axis(loc='right',axes=par2,offset=(offset1,0))
par2.axis['right'].toggle(all=True)
par3.axis['right']=new_fixed_axis(loc='right',axes=par3,offset=(offset2,0))
par3.axis['right'].toggle(all=True)

host.set_xlabel('Time')
host.set_ylabel('y1')
par1.set_ylabel('y2')
par2.set_ylabel('y3')
par3.set_ylabel('y4')

p1,=host.plot(df['time'],df['y1'])
p2,=par1.plot(df['time'],df['y2'])
p3,=par2.plot(df['time'],df['y3'])
p4,=par3.plot(df['time'],df['y4'])

host.set_ylim(0,5)
par1.set_ylim(0,8)
par2.set_ylim(0,10)
par3.set_ylim(0,15)

host.legend(loc='upper left',bbox_to_anchor=(0,-.15),ncol=4) 
host.axis['left'].label.set_color(p1.get_color())
host.axis["left"].label.set_rotation(90)

par1.axis['right'].label.set_color(p2.get_color())
par1.axis["right"].label.set_rotation(-90)

par2.axis['right'].label.set_color(p3.get_color())
par2.axis["right"].label.set_rotation(-90)

par3.axis['right'].label.set_color(p4.get_color())
par3.axis["right"].label.set_rotation(-90)

plt.draw()
plt.show()

Answer 1

I have a solution for the first problem, and an ugly hack for the second.

1) Rotate x-axis text

You need to set this using the host.axis property, and then move the legend and xlabel down a bit to make room:

host.legend(loc='upper left',bbox_to_anchor=(0,-.3),ncol=4)  # Lower legend a bit
host.axis["bottom"].label.set_pad(50)  # Lower x-label a bit
host.axis["bottom"].major_ticklabels.set(  # This is the actual rotation command
    rotation=90, verticalalignment='center', horizontalalignment='right', pad=-2)

2) Move y-labels to the top of axes

Nothing I tried here worked. Specifically, I expected the following to work:

par1.axis["right"].label.set_position((1.0, 1.0))

But the respective get_position command keeps returning (1.0, 0.5) , in which 0.5 is the middle of the axis. For some reason the 'set' command simply won't stick. This is where the ugly hack comes in - adding blank lines below the label . So where you set the label text, change to:

new_line_pos_fix = ''.join(['\n'] * 9)  # 9 is the number of blank lines; change as needed
host.set_ylabel('y1' + new_line_pos_fix)
par1.set_ylabel('y2' + new_line_pos_fix)
par2.set_ylabel('y3' + new_line_pos_fix)
par3.set_ylabel('y4' + new_line_pos_fix)

Now we just need to set the vertical alignment of the labels, so that the blank lines take effect, adding some padding for better readability:

host.axis['right'].label.set(verticalalignment='bottom', pad=7)
par1.axis['right'].label.set(verticalalignment='bottom', pad=7)
par2.axis['right'].label.set(verticalalignment='bottom', pad=7)
par3.axis['right'].label.set(verticalalignment='bottom', pad=7)

The above commands can be combined with the color and rotation settings, if you want more organized code, eg:

par1.axis['right'].label.set(color=p2.get_color(), rotation=-90, verticalalignment='bottom', pad=7)

Result: