title: Plot time series matplotlib with lots of data points
body: <p>I want to plot a time series for a dataset which has data for 12 months. However the data is recorded for every hour of every day for the 12months. The whole dataset is over 8000 datapoints. The data is in the following format</p>
  
  <pre><code>        Date   Time  Energy
  0 2014-01-01   1     1118.1
  1 2014-01-01   2     1233.2
  2 2014-01-01   3     1278.2
  .     .        .      .  
  23 2014-01-01  24    1125.3
  24 2014-01-02  1     1213.3
  .    .         .      .
  </code></pre>
  
  <p>When I plot it like this</p>
  
  <pre><code>plt.plot(energy['Date'], energy['Energy'])
  plt.xlabel('Date')
  plt.ylabel('Energy')
  </code></pre>
  
  <p>I get the following output
  <a href="https://i.stack.imgur.com/QS2zh.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/QS2zh.png" alt="time series"></a></p>
  
  <p>This graph doesn't make much sense because I cant observe any trends. I instead want to plot the average energy for each day. Any other suggestions about how to plot this time series in such a way that I observe any trends is welcome</p>