title: nchar() throwing unused argument (keepNA = TRUE)
body: <pre><code>x &lt;- c("asfef", "qwerty", "NA", "b", "stuff.blah.yech")
  nchar(x, keepNA= TRUE)
  </code></pre>
  
  <p>The above command is throwing me an error:</p>
  
  <blockquote>
    <p>unused argument (keepNA = TRUE)</p>
  </blockquote>
  
  <p>Can anybody help me in telling why is it throwing an error and what can be done to overcome it?</p>