title: Removing data from one dataframe that exists in another dataframe R
body: <p>I want to remove data from a dataframe that is present in another dataframe. Let me give an example:</p>
  
  <pre><code>letters&lt;-c('a','b','c','d','e')
  numbers&lt;-c(1,2,3,4,5)
  list_one&lt;-data.frame(letters,numbers)
  </code></pre>
  
  <p>I want to remove every row in list_one with matches in letters to this other dataframe:</p>
  
  <pre><code>letters2&lt;-c('a','c','d')
  list_two&lt;-data.frame(letters2)
  </code></pre>
  
  <p>I should mention that I'm actually trying to do this with two large csv files, so I really can't use the negative expression - to take out the rows.</p>
  
  <p>And create a final dataframe which only has the letters b and e and their corresponding numbers. How do I do this? </p>
  
  <p>I'm new to R so it's hard to research questions when I'm not quite sure what key terms to search. Any help is appreciated, thanks!</p>