title: Rbind with new columns and data.table
body: <p>I need to add many large tables to an existing table, so I use rbind with the excellent package data.table. But some of the later tables have more columns than the original one (which need to be included). Is there an equivalent of rbind.fill for data.table?</p>
  
  <pre><code>library(data.table)
  
  aa &lt;- c(1,2,3)
  bb &lt;- c(2,3,4)
  cc &lt;- c(3,4,5)
  
  dt.1 &lt;- data.table(cbind(aa, bb))
  dt.2 &lt;- data.table(cbind(aa, bb, cc))
  
  dt.11 &lt;- rbind(dt.1, dt.1)  # Works, but not what I need
  dt.12 &lt;- rbind(dt.1, dt.2)  # What I need, doesn't work
  dt.12 &lt;- rbind.fill(dt.1, dt.2)  # What I need, doesn't work either
  </code></pre>
  
  <p>I need to start rbinding before I have all tables, so no way to know what future new columns will be called. Missing data can be filled with NA.</p>