title: Removing stop words with dplyr
body: <p>Reading <a href="http://tidytextmining.com/tidytext.html" rel="nofollow noreferrer">http://tidytextmining.com/tidytext.html</a> states : </p>
  
  <blockquote>
    <p>"</p>
    
    <p>Often in text analysis, we will want to remove stop words; stop words
    are words that are not useful for an analysis, typically extremely
    common words such as “the”, “of”, “to”, and so forth in English. We
    can remove stop words (kept in the tidytext dataset stop_words) with
    an anti_join().</p>
    
    <p>data(stop_words)</p>
    
    <p>tidy_books &lt;- tidy_books %>%   anti_join(stop_words)</p>
    
    <p>"</p>
  </blockquote>
  
  <p>I'm attempting to modify to remove stop words from a string :</p>
  
  <pre><code>data(stop_words)
  str_v &lt;- paste(c("this is a test"))
  str_v &lt;- str_v %&gt;%
    anti_join(stop_words)
  </code></pre>
  
  <p>but returns error :</p>
  
  <pre><code>Error in UseMethod("anti_join") : 
    no applicable method for 'anti_join' applied to an object of class "character"
  </code></pre>
  
  <p>Do need to convert str_v to class that contains method <code>anti_join</code> ?</p>