title: Keep zoom when updating pyplot
body: <p>I update a live plot in a pyplot window with something like this:</p>
  
  <pre><code>while True:
      plt.plot(x,y)
      plt.pause(0.005)
      plt.clf()
  </code></pre>
  
  <p>However, when I zoom and/or pan in the pyplot window, the view resets on every <code>plt.clf()</code>.</p>
  
  <p>Is there a way to keep the zoom? Maybe saving and restoring the view state somehow? Maybe not using <code>plt.clf()</code>, which apparently deletes line handles, but instead update the data of my lines and redraw?</p>