title: Changing the formatting of a datetime axis in matplotlib
body: <p>I have a series whose index is <code>datetime</code> that I wish to plot. I want to plot the values of the series on the y axis and the index of the series on the x axis. The <code>Series</code> looks as follows:</p>
  <pre><code>2014-01-01     7
  2014-02-01     8
  2014-03-01     9
  2014-04-01     8
  ...
  </code></pre>
  <p>I generate a graph using <code>plt.plot(series.index, series.values)</code>. But the graph looks like:</p>
  <p><a href="https://i.stack.imgur.com/bC92r.png" rel="noreferrer"><img src="https://i.stack.imgur.com/bC92r.png" alt="graph" /></a></p>
  <p>The problem is that I would like to have only year and month (yyyy-mm or 2016 March). However, the graph contains hours, minutes and seconds. How can I remove them so that I get my desired formatting?</p>