title: merge list changes date format to numeric
body: <p>I have list of length 18 , when I tried to merge these list for creating data frame it changes format for date to numeric.</p>
  
  <p>I have used below syntax </p>
  
  <pre><code>forecast_data = do.call(rbind, datalist)
  </code></pre>
  
  <p>there are 3 dates column all changed to numeric when I execute above code.</p>
  
  <p>Is there a way I can keep type of date column as date only while merging list. Please advice. </p>
  
  <p>Please refer to below sample list and result which I want to achieve from set of list</p>
  
  <pre><code>datalist = list()
  
  l &lt;- data.frame(ID=c(1), Date=as.Date("2017-07-02"), Prediction=c(66))
  l &lt;- as.list(l)
  datalist[[1]] &lt;- (l)
  
  l &lt;- data.frame(ID=c(1), Date=as.Date("2017-07-09"), Prediction=c(70))
  l &lt;- as.list(l)
  datalist[[2]] &lt;- (l)
  
  l &lt;- data.frame(ID=c(1), Date=as.Date("2017-07-16"), Prediction=c(77))
  l &lt;- as.list(l)
  datalist[[3]] &lt;- (l)
  
  
  result &lt;- data.frame(ID=c(1,1,1), Date=c("2017-07-02","2017-07-09","2017-07-16"), Prediction=c(66,70,77))
  </code></pre>