Pylab - Adjust hspace for some of the subplots

Question

I have a plot in which I want to have one panel separate from other four panels. I want the rest of the four panels to share the x axis. The figure is shown below. I want the bottom four panels to have shared x-axis. I tried

f = plt.figure()
ax6=f.add_subplot(511)
ax4=f.add_subplot(515)
ax1=f.add_subplot(512,sharex=ax4)
ax2=f.add_subplot(513,sharex=ax4)
ax3=f.add_subplot(514,sharex=ax4)

However, that does not work for me. The attached figure is made with

f = plt.figure()
ax6=f.add_subplot(511)
ax4=f.add_subplot(515)
ax1=f.add_subplot(512)
ax2=f.add_subplot(513)
ax3=f.add_subplot(514)

and then setting the xticks to none by

ax1.get_xaxis().set_ticklabels([])
ax2.get_xaxis().set_ticklabels([])
ax3.get_xaxis().set_ticklabels([])

using f.subplots_adjust(hspace=0) joins all the subplots. Is there a way to join only the bottom four panels?

Thanks!

Answer 1

It's easiest to use two separate gridspec objects for this. That way you can have independent margins, padding, etc for different groups of subplots.

As a quick example:

import numpy as np
import matplotlib.pyplot as plt

# We'll use two separate gridspecs to have different margins, hspace, etc
gs_top = plt.GridSpec(5, 1, top=0.95)
gs_base = plt.GridSpec(5, 1, hspace=0)
fig = plt.figure()

# Top (unshared) axes
topax = fig.add_subplot(gs_top[0,:])
topax.plot(np.random.normal(0, 1, 1000).cumsum())

# The four shared axes
ax = fig.add_subplot(gs_base[1,:]) # Need to create the first one to share...
other_axes = [fig.add_subplot(gs_base[i,:], sharex=ax) for i in range(2, 5)]
bottom_axes = [ax] + other_axes

# Hide shared x-tick labels
for ax in bottom_axes[:-1]:
    plt.setp(ax.get_xticklabels(), visible=False)

# Plot variable amounts of data to demonstrate shared axes
for ax in bottom_axes:
    data = np.random.normal(0, 1, np.random.randint(10, 500)).cumsum()
    ax.plot(data)
    ax.margins(0.05)

plt.show()