title: Remove Rows From Data Frame where a Row matches a String
body: <p>I do I remove all rows in a dataframe where a certain row meets a string match criteria?</p>
  
  <p>For example:</p>
  
  <pre><code>A,B,C
  4,3,Foo
  2,3,Bar
  7,5,Zap
  </code></pre>
  
  <p>How would I return a dataframe that excludes all rows where C = Foo:</p>
  
  <pre><code>A,B,C
  2,3,Bar
  7,5,Zap
  </code></pre>