title: How to plot events on time on using matplotlib
body: <p>I have 3 lists, each containing numbers, representing a time. The time represents occuring of an event. For example, in this <code>A</code>, I have a number for each occurence of event <code>A</code>. I want to represent this data on a graph. In either of the following two ways:</p>
  
  <p>1)</p>
  
  <pre><code>aabaaabbccacac
  </code></pre>
  
  <p>2)</p>
  
  <pre><code>a-&gt; xx xxx    x x
  b-&gt;   x   xx  
  c-&gt;         xx x x
  </code></pre>