title: How to plot time series in seaborn with one day a x label?
body: <p>I have a dataframe which represents a time series of five days with one day 48 rows of data like: </p>
  
  <pre><code>   Density Value     start time
         0.328336  2012-01-16 00:00:00
         1.195605  2012-01-16 00:30:00
         2.398546  2012-01-16 01:00:00
         1.320956  2012-01-16 01:30:00
         1.292287  2012-01-16 02:00:00
         1.286741  2012-01-16 02:30:00
         ...
         0.199826  2012-01-20 23:00:00
         0.437794  2012-01-20 23:30:00
  </code></pre>
  
  <p>I tried to use <code>seaborn</code> to draw a time series graph with one day only one label on time axis, which means there are only 5 labels (from 2012-01-16 to 2012-01-20) on x-axis. I have tried <code>seaborn.tsplot</code> like <code>sns.tsplot(data=density_list,time=start_time_list)</code> but only get the axis labels as the following picture shows:
  <a href="https://i.stack.imgur.com/KD0A3.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/KD0A3.png" alt="enter image description here"></a></p>
  
  <p>I am wondering how I can get the x labels I want in this case. Thanks!</p>