Creating a certain plot is a lot of work, so I would like to automate this by create a function f() that returns a figure.

I would like to call this function so that I can put the result in a subplot. Is there anyway I can do this? Below is some psuedo code explaining what I mean

figure_of_interest = f()fig,ax = plt.subplots(nrows = 4,cols = 1)ax[1].replace_with(figure_of_interest)

This was asked before here and here.

Short answer: It is not possible.

But you can always modify the axes instance or use a function to create/modify the current axes:

import matplotlib.pyplot as plt
import numpy as npdef test():x = np.linspace(0, 2, 100)# With subplotsfig1, (ax1, ax2) = plt.subplots(2)plot(x, x, ax1)plot(x, x*x, ax2)# Another Figure without using axesfig2 = plt.figure()plot(x, np.exp(x))plt.show()def plot(x, y, ax=None):if ax is None:ax = plt.gca()line, = ax.plot(x, y)return linetest()