title: Using grepl() to remove values from a dataframe in R
body: <p>I have a <code>data.frame</code> with 1 column, and a nondescript number of rows. </p>
  
  <p>This column contains strings, and some strings contain a substring, let's say <code>"abcd"</code>. </p>
  
  <p>I want to remove any strings from the database that contain that substring. For example, I may have five strings that are <code>"123 abcd"</code>, and I want those to be removed.</p>
  
  <p>I am currently using <code>grepl()</code> to try and remove these values, but it is not working. I am trying:</p>
  
  <pre><code>data.frame[!grepl("abcd", dataframe)]
  </code></pre>
  
  <p>but it returns an empty data frame.</p>