title: How to plot timedelta as value with matplotlib
body: <p>I am trying to plot a duration in seconds with respect to some iteration values. I compute the duration values by substracting two datetime values. Then, I would like to plot these results in a very simple way using existing tools.</p>
  
  <p>My code is the following but it doesn't work yet:</p>
  
  <pre class="lang-py prettyprint-override"><code>#!/usr/bin/env python
  
  import datetime
  import matplotlib.pyplot as plt
  from numpy import arange
  
  it = arange(10)
  durations = [datetime.timedelta(hours=h+30) for h in it]
  
  plt.plot(it, durations)
  
  plt.show()
  </code></pre>
  
  <p>I got the following error:</p>
  
  <pre><code>TypeError: float() argument must be a string or a number
  </code></pre>
  
  <p>I know that I can make it work by using datetime instead of timedelta but my goal is to plot duration in hours (around 40 hours) so the rendering is not good.</p>