title: How would I add a Total Row for each value in a specific column, that does calculations based upon other columns,
body: <p>Assume I have this data frame</p>
  
  <p><a href="https://i.stack.imgur.com/GNjAU.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/GNjAU.png" alt="enter image description here"></a></p>
  
  <p>What I want is this</p>
  
  <p><a href="https://i.stack.imgur.com/bIVmL.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/bIVmL.png" alt="enter image description here"></a></p>
  
  <p>What I want to do is create rows which groups upon the month variable, which then obtains the sum of the total variable, and the unique value of the days_month variable for all of the values in person for that month.</p>
  
  <p>I am just wondering if there is an easy way to do this that does not involve multiple spreads and gathers with adorn totals that I have to change the days in month back to original value after the totals were summed, etc.  Is there a quick and easy way to do this?</p>