title: Pandas Counting Unique Rows
body: <p>I have a pandas data frame similar to:</p>
  
  <pre><code>ColA ColB
  1    1
  1    1
  1    1
  1    2
  1    2
  2    1
  3    2
  </code></pre>
  
  <p>I want an output that has the same function as <a href="https://docs.python.org/2/library/collections.html#collections.Counter" rel="noreferrer">Counter</a>.  I need to know how many time each row appears (with all of the columns being the same.</p>
  
  <p>In this case the proper output would be:</p>
  
  <pre><code>ColA ColB Count
  1    1    3
  1    2    2
  2    1    1
  3    2    1
  </code></pre>
  
  <p>I have tried something of the sort:</p>
  
  <pre><code>df.groupby(['ColA','ColB']).ColA.count()
  </code></pre>
  
  <p>but this gives me some ugly output I am having trouble formatting</p>