title: How to "clean the slate"?
body: <p>I want to make a series of plots, and save each to a file. But I don't know how to wipe previous plots off. Maybe I need to create some new object for each time, but I don't which object that would be. Here is my code, notice the comment.
  This is my code:</p>
  
  <pre><code>import matplotlib.pyplot as plt
  ind = (1,2,3,4)
  groups=(
    (1, (1.1,1.2,1.3,1.4)),
    (2, (2.2,2.2,1.2,2.4)),
  )
  
  for group in reversed(groups):
    #clean the slate ?
    plt.bar(ind   ,group[1])
    plt.xticks([i+0.5 for i in ind],ind)
    plt.savefig('%d.png' % group[0])
  </code></pre>