title: Activate a figure in matplotlib
body: <p>It seems easy but I could not find any solution for opening multiple figures and save them by their name. I look for something like this:</p>
  
  <pre><code>fig1, ax1 = pl.subplots(1)
  fig2, ax2 = pl.subplots(1)
  ...
  pl.savefig('f1.png', fig1)
  pl.savefig('f2.png', fig2)
  </code></pre>
  
  <p>usually <code>pl.savefig</code> acts on the last active figure. So how one can activate a figure and save it, then repeat the process for the rest of the figures?</p>