title: How to unlist result of lapply involving function(x) as.Date(as.POSIXct(x, origin = "1970-01-01"))
body: <p>I've got a list that is the result of the following command:</p>
  
  <pre><code>lapply(data$displayDate, function(x) as.Date(as.POSIXct(x, origin = "1970-01-01")))
  </code></pre>
  
  <p>That comes out looking like this:</p>
  
  <pre><code>&gt; data$displayDateDay[1:10]
  [[1]]
  [1] "2015-05-02"
  
  [[2]]
  [1] "2015-05-10"
  
  [[3]]
  [1] "2015-05-10"
  
  [[4]]
  [1] "2015-05-10"
  
  [[5]]
  [1] "2015-05-11"
  
  [[6]]
  [1] "2015-05-12"
  
  [[7]]
  [1] "2015-05-12"
  
  [[8]]
  [1] "2015-05-13"
  
  [[9]]
  [1] "2015-05-13"
  
  [[10]]
  [1] "2015-05-26"
  </code></pre>
  
  <p>This is all well and good but I can't figure out how to get this back into a property column vector in my data table. If I try to <code>unlist</code> this list, here's what I get:</p>
  
  <pre><code>&gt; unlist(testVector)
   [1] 16557 16565 16565 16565 16566 16567 16567 16568 16568 16581
  </code></pre>
  
  <p>The class is numeric, whereas I wanted a date. Why is this happening, and how can I achieve a vector of dates?</p>