title: Plot three grouped columns of data in R ggplot2
body: <p>I have data that resembles the following:</p>
  
  <pre><code>Ref Var Obs 
  A   A   2   
  A   C   6   
  A   T   8   
  A   G   2   
  C   A   9   
  C   C   1   
  C   T   8   
  C   G   4   
  T   A   6   
  T   C   1   
  T   T   9   
  T   G   6   
  G   A   3   
  G   C   1   
  G   T   7   
  G   G   2
  </code></pre>
  
  <p>And I am trying to use qplot to plot the data but I'm not sure how to display three columns of information instead of just two, and in a grouped maner. I would like to plot a bar plot with number of <code>obs</code> on the y axis and <code>var</code> on the x-axis grouped by <code>ref</code>. The following is the idea of what I am trying to do:</p>
  
  <p><a href="https://i.stack.imgur.com/1mTBr.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/1mTBr.jpg" alt="example plot"></a></p>