title: matplotlib: change yaxis tick labels
body: <p>For each tick label on the y axis, I would like to change:
  <code>label -&gt; 2^label</code></p>
  
  <p>I am plotting log-log data (base 2), but I would like the labels to show the original data values.</p>
  
  <p>I know I can get the current y labels with 
  <code>ylabels = plt.getp(plt.gca(), 'yticklabels')</code></p>
  
  <p>This gives me a list: <code>&lt;a list of 9 Text yticklabel objects&gt;</code>
  each of which is a <code>&lt;matplotlib.text.Text object at 0x...&gt;</code></p>
  
  <p>I looked at the documentation of the text objects at <a href="http://matplotlib.org/users/text_props.html" rel="noreferrer">http://matplotlib.org/users/text_props.html</a>
  but I'm still not sure what the correct syntax is to change the string in each text label.</p>
  
  <p>Once I change the labels, I could set them on the axis using:</p>
  
  <p><code>plt.setp(plt.gca(), 'yticklabels', ylabels)</code> </p>