Create multiple columns and rows of unequal size in matplotlib

Question

I need to create multiple columns and rows of unequal size in matplotlib. Here is a sample code:

a = np.random.rand(20, 20)
b = np.random.rand(20, 5)
c = np.random.rand(5, 20)
d = np.random.rand(5,5)
arrays = [a,b,c,d]
fig, axs = plt.subplots(2, 2, sharex='col', sharey= 'row', figsize=(10,10))
for ax, ar in zip(axs.flatten(), arrays):
    ax.imshow(ar)

However, I get this as a result.

The right column has images of unequal width for the first and second row, and I would want them to be equal (basically shrink the bottom right image to have the same scale as other images). I had researched this a fair amount, but nothing seems to work. I had tried tight_layout(), some other formatting tricks, all to no avail...

Answer 1

You can use the gridspec's height_ratios and width_ratios argument to set the desired proportion the subplots shall occupy.

In this case, due to the symmetry, this is simply the shape of eg b .

import numpy as np
import matplotlib.pyplot as plt

a = np.random.rand(20, 20)
b = np.random.rand(20, 5)
c = np.random.rand(5, 20)
d = np.random.rand(5,5)
arrays = [a,b,c,d]
fig, axs = plt.subplots(2, 2, sharex='col', sharey= 'row', figsize=(10,10), 
                        gridspec_kw={"height_ratios" : b.shape, 
                                     "width_ratios" : b.shape})
for ax, ar in zip(axs.flatten(), arrays):
    ax.imshow(ar)

plt.show()

Or, more generally,

gridspec_kw={"height_ratios" : [a.shape[0], c.shape[0]], 
              "width_ratios" : [a.shape[1], b.shape[1]]}