title: Convert xml_nodeset to data.frame
body: <p>I am using <code>rvest</code>. And I would like to convert the result to a data frame:</p>
  
  <pre><code>&gt; links &lt;- pgsession %&gt;% jump_to(urls[2])  %&gt;%  read_html() %&gt;% html_nodes("a")    
  &gt; links
  {xml_nodeset (114)}
   [1] &lt;a href="/Mitglieder/Detail/1213412"&gt;Date&lt;/a&gt;
   [2] &lt;a href="/Account/ChangePassword"&gt;Kennwort Ã¤ndern&lt;/a&gt;
   [3] &lt;a href="/Account/BenutzernamenAendern/124312234"&gt;Benutzernamen Ã¤ndern&lt;/a&gt;
   [4] &lt;a href="/Account/LogOff"&gt;Abmelden&lt;/a&gt;
  ...    
  </code></pre>
  
  <p>I used the following method:</p>
  
  <pre><code>library(plyr)
  ldply(xmlToList(links), data.frame)
  Error in UseMethod("xmlSApply") : 
      no applicable method for 'xmlSApply' applied to an object of class "xml_nodeset"
  df1 &lt;- data.frame(character(13000))
  df1 &lt;- rbind(df1, data.frame(links ))# append to data.frame
  </code></pre>
  
  <p>However, I get an error:</p>
  
  <pre><code>Error in UseMethod("xmlSApply") : 
      no applicable method for 'xmlSApply' applied to an object of class "xml_nodeset"
  </code></pre>
  
  <p>Any suggestion what I am doing wrong?</p>
  
  <p>I appreciate your replies!    </p>