title: Create a new variable in Tableau
body: <p>I am new to Tableau and trying to get myself oriented to this system. I am an R user and typically work with wide data formats, so getting things wrangled into the proper long format has been tricky.  Here is my current problem.  </p>
  
  <p>Assume I have a data file that is structured as such</p>
  
  <pre><code>ID       Disorder     Value
  1         A             0     
  1         B             1
  1         C             0
  2         A             1
  2         B             1
  2         C             1
  3         A             0
  3         B             0
  3         C             0
  </code></pre>
  
  <p>What I would like to do is to combine the variables, such that the presence of a set of disorders are used for summary variables.  For example, how could I go about achieving something like this as my output?  The sum is the number of people with the disorder, and the percentage is the number of people with the disorder divided by the total number of people.</p>
  
  <pre><code>Disorders        Sum       Percentage
  A                 1            33.3 
  B                 2            66.6
  C                 1            33.3
  AB                2            66.6
  BC                2            66.6
  AC                1            33.3
  ABC               2            66.6
  </code></pre>