title: How to plot evenly spaced values on the x axis while plotting using matplotlib
body: <p>I have a Series with more than 100 000 rows that I want to plot. I have problem with the x-axis of my figure. Since my x-axis is made of several dates, you can't see anything if you plot all of them. </p>
  
  <p>How can I choose to show only 1 out of every x on the x-axis ?</p>
  
  <p>Here is an example of a code which produces a graphic with an ugly x-axis :</p>
  
  <pre><code>sr = pd.Series(np.array(range(15)))
  sr.index = [ '2018-06-' + str(x).zfill(2) for x in range(1,16)]
  Out : 
  2018-06-01     0
  2018-06-02     1
  2018-06-03     2
  2018-06-04     3
  2018-06-05     4
  2018-06-06     5
  2018-06-07     6
  2018-06-08     7
  2018-06-09     8
  2018-06-10     9
  2018-06-11    10
  2018-06-12    11
  2018-06-13    12
  2018-06-14    13
  2018-06-15    14
  
  fig = plt.plot(sr)
  plt.xlabel('Date')
  plt.ylabel('Sales')
  </code></pre>