title: I need split vector in diffrent column each factor R
body: <p>My data have different length factors like this. </p>
  
  <pre><code>variable &lt;- c("A,B,C","A,B","A,C","B,C")
  </code></pre>
  
  <p>I had used <code>strsplit</code> and other similar function, but I can't solve my problem</p>
  
  <p>I need to get a data.frame like this</p>
  
  <pre><code>   A   B  C
  1  A   B  C
  2  A   B  NA
  3  A   NA C
  4  NA  B  C
  </code></pre>
  
  <p><strong>Thanks</strong></p>