title: transform a dataframe to and make it similar to an R frequency table
body: <p>I have a data frame that has frequency counts. I created this data frame using dplyr's group by</p>
  
  <pre><code>a   beta    2
  a   gamma   2
  b   alpha   3
  b   beta    5
  b   gamma   9
  c   beta    3
  c   gamma   10
  d   beta    8
  </code></pre>
  
  <p>I am trying to create a frequency table that aggregates the counts that look like a frequency table using R's table function </p>
  
  <pre><code>        a   b   c   d
  alpha   0   3   0   0
  beta    2   5   3   8
  gamma   2   9   10  4
  </code></pre>