title: Remove part of character string in data frame
body: <p>I'm struggling to delete the strings <code>"D_1__"</code> , <code>"D_2__"</code> , <code>"D_3__"</code> , etc. in a <code>data.frame</code> while keeping the succeeding text, i.e. input: <code>"D_1__succeeding text"</code> output: <code>"succeeding text"</code>.</p>
  
  <p>I tried</p>
  
  <pre><code>df &lt;- gsub("D_.__", "", df)
  </code></pre>
  
  <p>but nothing was changed</p>
  
  <p>Further the columns of the imported <code>data.frame</code> are <code>factors</code> with more than one level. May this be causing the problem and how can I convert the <code>df</code>? </p>
  
  <p>Thanks a lot for you help!</p>