title: Adding a subplot that doesn't share an x axis when others do
body: <p>I'm trying to add a subplot onto the bottom of a figure of subplots. The issue I've got is that all of the first set of subplots want to share their x axis, but not the bottom one.</p>
  
  <p><code>channels</code> are the subplots that want to share the x axis.</p>
  
  <p>So how can I add a subplot that does not share the x axis?
  This is my code:</p>
  
  <pre><code>def plot(reader, tdata):
      '''function to plot the channels'''
  
  channels=[]
          for i in reader:
          channels.append(i)
  
      fig, ax = plt.subplots(len(channels)+1, sharex=False, figsize=(30,16), squeeze=False)
      plot=0
      #where j is the channel name
      for i, j in enumerate(reader): 
  
          y=reader["%s" % j]
          ylim=np.ceil(np.nanmax(y))
          x=range(len((reader["%s" % j])))
          ax[plot,0].plot(y, lw=1, color='b')
          ax[plot,0].set_title("%s" % j)
          ax[plot,0].set_xlabel('Time / s')
          ax[plot,0].set_ylabel('%s' % units[i])
          ax[plot,0].set_ylim([np.nanmin(y), ylim+(ylim/100)*10])
          plot=plot+1
  
      ###here is the new subplot that doesn't want to share the x axis###
      ax[plot, 0].plot()
      plt.tight_layout()
      plt.show()
  </code></pre>
  
  <p>This code does <strong>NOT</strong> work because they are shareing the x-axis of the last subplot. The length of channels changes dependant onn what I specify earlier in the code.</p>
  
  <p>Is it a valid option to use <code>add_subplot</code> somehow, ever though I don't have a constant number of channels? </p>
  
  <p>thanks so much for any help</p>
  
  <p><strong>EDIT</strong>
  Image for Joe:</p>
  
  <p><img src="https://i.stack.imgur.com/bj8nF.png" alt="enter image description here"></p>