如何控制matplotlib中图形周围的空白？（plt.tight_layout不起作用）

Question

I have a matplotlib figure with 3 sub-plots. The consensus from stackexchange seems to be to use the plt.tight_layout in order to get rid of the whitespace around the figure. This does not solve the problem in my case.

My code is as follows:

import numpy as np
import os
import pandas as pd
import matplotlib as mpl
from matplotlib import pyplot as plt

my_dpi = 1500
plt.ion()

index = np.linspace(0,5,10)
combined = np.linspace(0,1,10)
case1 = np.linspace(0,1,10)
case2 = np.linspace(0,1,10)
case3 = np.linspace(0,1,10)

tsfont = {'fontname':'Times-Roman'}
mpl.rcParams.update({'font.size': 18})
mpl.rc('font',family='Arial')
ms = 0

f = plt.figure()
f.set_size_inches(7.5,10)
f.axison=False


lw = 2
asp = 5


axarr1 = plt.subplot(3,1,1, adjustable='box',aspect = asp)

axarr1.set_xlim(0,5,10)
axarr1.set_ylim(0,1)
axarr1.set_ylabel('y')
axarr1.set_xlabel('$\\tau$', fontsize =25)
p = axarr1.plot(index,combined,color='navy', linewidth=lw, label = "Healthy")
axarr1.xaxis.set_label_coords(0.5, -0.05)


'''
Duct 2
'''

axarr2 = plt.subplot(3,1,2, adjustable='box',aspect = asp)
#axarr2.set_aspect('auto')
axarr2.set_xlim(0,5,10)
axarr2.set_ylim(0,1)
axarr2.set_ylabel('y')
axarr2.set_xlabel('$\\tau$', fontsize = 25)
g = axarr2.plot(index,combined,color='navy', linewidth=lw)
axarr2.xaxis.set_label_coords(0.5, -0.05)

'''
Duct 3
'''

axarr3 = plt.subplot(3,1,3, adjustable='box',aspect = asp)

axarr3.set_xlim(0,5,10)
axarr3.set_ylim(0,1)
axarr3.set_ylabel('y')
axarr3.set_xlabel('$\\tau$', fontsize = 25)
w = axarr3.plot(index,combined,color='navy', linewidth=lw)
axarr3.xaxis.set_label_coords(0.5, -0.05)

#plt.tight_layout()
plt.show()

Without using plt.tight_layout() I get the following result

Uncommenting the relevant line gives me

As is obvious, while the vertical spacing changes, the horizontal spacing does not

I'd like to know how to get rid of the horizontal whitespacing to the left and right.

Answer 1

The tight_layout option places the images closer to the borders. However, in your case, there is nothing to fill this empty space with, so it doesn't work.

If you want a narrower figure, you should change the horizontal dimension, eg:

plt.figure(..., tight_layout=True, figsize=(12, 5))

This is in inches, experiment with the numbers until it looks good.

You could also use 2 by 2 subplots to keep a square figure and use the space better:

plt.subplot(2, 2, ...)

although this may look suboptimal with a prime number of figures.