title: Python plot x-axis display only select items
body: <p>I have a python matplotlib graph showing up as below.</p>
  
  <p>There are over 100 items on the X-axis and I DO want to plot them all, but want only about 25 or so (maybe automatically) so that it is clear to look at. </p>
  
  <p>Can you please help?</p>
  
  <p>Thanks</p>
  
  <p>My code is also as follows:</p>
  
  <pre><code>l1 = plt.plot(b)
  plt.setp(l1, linewidth=4, color='r')
  l2 = plt.plot(c)
  plt.setp(l2, linewidth=4, color='k')
  l3 = plt.plot(d)
  plt.setp(l3, linewidth=4, color='g')
  plt.xticks(range(len(a)), a)
  plt.xticks(rotation=30)
  plt.show()
  plt.savefig('a.png')
  </code></pre>
  
  <p>NOTE: I also have the data column a (the X-axis variable) in the form </p>
  
  <pre><code>u' 2016-02-29T00:01:30.000Z CHEPSTLC0007143 CDC-R114-DK'
  </code></pre>
  
  <p>which throws this error <code>invalid literal for float()</code>. That is the reason I am using <code>plt.xticks(range(len(a)), a)</code>. </p>
  
  <p><a href="https://i.stack.imgur.com/MZMsD.png" rel="noreferrer"><img src="https://i.stack.imgur.com/MZMsD.png" alt=""></a></p>