How to create vertical subplot in Python using Matplotlib?-CodePudding

I have 2 plots in python and when plotting them separately as done in the first 2 sections of codes, it correctly displays the first 2 graphs. However, when trying to make a subplot of the 2 graphs beneath each other, the following picture is rendered by python. What am I doing wrong here?

K1 = 1
K2 = [[0. 0. 0.]
      [0. 3. 0.]
      [0. 0. 0.]]

# visualizing the source function
plt.clf()
plt.imshow([[K1, K1],
            [K1, K1]], cmap='viridis')
plt.colorbar()
plt.show()

plt.clf()
plt.imshow(K2, cmap='viridis')
plt.colorbar()
plt.show()

# visualizing the source function
plt.clf()
plt.imshow([[K1, K1],
            [K1, K1]], cmap='viridis')
plt.colorbar()
plt.subplot(2, 1, 1)


plt.clf()
plt.imshow(K2, cmap='viridis')
plt.colorbar()
plt.subplot(2, 1, 2)
plt.show()

CodePudding user response：

The plt.subplot() function needs to be on top of imshow(). Also, there is no need for clf() which is used only when you want to clear the current figure.

OPTION 1 (State-based):

plt.figure(figsize=(10, 10))
plt.subplot(2, 1, 2)
plt.imshow([[K1, K1],
            [K1, K1]], cmap='viridis')
plt.colorbar()
plt.subplot(2, 1, 1)
plt.imshow(K2, cmap='viridis')
plt.colorbar()
plt.show()

OPTION 2 (OOP):

fig, ax = plt.subplots(2, 1, figsize=(10, 10))
sub_1 = ax[0].imshow([[K1, K1],
                      [K1, K1]], cmap='viridis')
fig.colorbar(sub_1, ax=ax[0])
sub_2 = ax[1].imshow(K2, cmap='viridis')
fig.colorbar(sub_2, ax=ax[1])
plt.show()

output: