title: rbind() hundreds of .CSVs with filename metadata
body: <p>I have hundreds of .csv files that are structured like this:</p>
  
  <pre><code>xyz25012013 &lt;- data.frame(province = c("AB", "BC", "ON"), high = c(30, 20, 25), low = c(5, 2, 3))
  xyz13122014 &lt;- data.frame(province = c("AB", "BC", "ON"), high = c(20, 34, 25), low = c(1, 8, 3))
  xyz30042014 &lt;- data.frame(province = c("AB", "BC", "ON"), high = c(50, 21, 27), low = c(1, 9, 26))
  xyz04072015 &lt;- data.frame(province = c("AB", "BC", "ON"), high = c(26, 07, 90), low = c(4, 7, 3))
  </code></pre>
  
  <p>I want to import and merge/row bind all of them and retain the metadata date contained in the filename.</p>
  
  <p><code>as.Date(substr(&lt;filename&gt;,4,11) format = "%d%m%Y")</code></p>
  
  <p>I want the final output to look sort of like this:</p>
  
  <pre><code>date &lt;- c(rep("25012013", 3), rep("13122014", 3), rep("30042014", 3), rep("04072015", 3))
  xyz &lt;- rbind(xyz25012013, xyz13122014, xyz30042014, xyz04072015)
  xyz &lt;- cbind(xyz, date)
  xyz$date &lt;- as.Date(xyz$date, format = "%d%m%Y")
  print(xyz)
  </code></pre>