title: Running total on a pandas df
body: <p>I am trying to add a running <code>count</code> to a <code>pandas df</code>.</p>
  
  <p>For the values in <code>Column A</code>, I want to add <code>'5'</code> and for values in <code>Column B</code> I want to add  <code>'1'</code>.</p>
  
  <p>So for the <code>df</code> below I'm hoping to produce:</p>
  
  <pre><code>   A  B Total
  0  0  0     0
  1  0  0     0
  2  1  0     5
  3  1  1     6
  4  1  1     6
  5  2  1    11
  6  2  2    12
  </code></pre>
  
  <p>So for every incremental <code>integer</code> in <code>Column A</code>, it equal <code>'5'</code> in the total. While <code>Column B</code> is the <code>'+1'</code>.</p>
  
  <p>I tried:</p>
  
  <pre><code>df['Total'] = df['A'].cumsum(axis = 0)
  </code></pre>
  
  <p>But this doesn't include Column B</p>