Python Subplots with shared axis loop

Question

I am trying to make a plot of subplots where each subplot comprises out of two subplots sharing the x-axis. I have tried the following code:

gs_top = plt.GridSpec(6, 3, hspace = 0.0001)
gs_base = plt.GridSpec(6, 3, hspace = 0.95)

f2 = plt.figure()

for i in range(9):
    up_id  = [0,1,2,6,7,8,12,13,15]
    bot_id = [3,4,5,9,10,11,15,16,17]

    axarr2 = f2.add_subplot(gs_top[up_id[i]])


    axarr2.plot()   

    ax_sub = f2.add_subplot(gs_base[bot_id[i]], sharex= axarr2) 
    ax_sub.imshow()
    axarr2.set_title('title')
    axarr2.xaxis.set_visible(False)

How should I set the parameters in plt.GridSpec()?

Answer 1

I would guess that you want to use gridspec.GridSpecFromSubplotSpec to create another gridspec inside a gridspec. So assuming you want a 3 x 3 grid and each cell shall comprise two subplots, vertically attached to each other and sharing their x axes.

import matplotlib.gridspec as gridspec
import matplotlib.pyplot as plt
import numpy as np

fig = plt.figure()
gs = gridspec.GridSpec(3, 3, hspace=0.6,wspace=0.3)

for i in range(9):
    gss = gridspec.GridSpecFromSubplotSpec(2, 1, subplot_spec=gs[i],
                                           hspace=0.0)

    ax0 = fig.add_subplot(gss[0])
    ax1 = fig.add_subplot(gss[1], sharex=ax0)

    x = np.linspace(0,6*np.pi)
    y = np.sin(x)
    ax0.plot(x,y)
    ax1.plot(x/2,y)

    ax0.set_title('title {}'.format(i))
    ax0.tick_params(axis="x", labelbottom=0)

plt.show()