title: Sum of previous rows values
body: <p>how I can sum previous rows values and current row value to a new column?
  My current output:</p>
  
  <pre><code>index,value
  0,1
  1,2
  2,3
  3,4
  4,5
  </code></pre>
  
  <p>My goal output is:</p>
  
  <pre><code>index,value,sum
  0,1,1
  1,2,3
  2,3,6
  3,4,10
  4,5,15
  </code></pre>
  
  <p>I know that this is easy to do with Excel, but I'm looking solution to do with pandas.</p>
  
  <p>My code:</p>
  
  <pre><code>import random, pandas
  
  recordlist=[1,2,3,4,5]
  
  df=pandas.DataFrame(recordlist, columns=["Values"])
  </code></pre>