title: Convert NA values to Date in R
body: <p>Is there a way to convert NA values to Date.</p>
  <pre><code>asdd &lt;- data.frame(a = as.Date(c(NA, &quot;1970-01-01&quot;)), b = c(2,3))
  asdd &lt;- as.data.table(asdd)
  asdd
              a b
  1:       &lt;NA&gt; 2
  2: 1970-01-01 3
  
  asdd [,a := ifelse(is.na(a), as.Date(today()+360),a)]
  asdd
         a b
  1: 19580 2
  2:     0 3
  </code></pre>
  <p>Expected output</p>
  <pre><code>asdd
         a      b
  1: 2023-08-11 2
  2: 1970-01-01 3
  </code></pre>
  <p>Can we achieve this ouptut?</p>