an><span class='op'>[</span><span class='fl'>1</span><span class='op'>:</span><span class='fl'>6</span><span class='op'>]</span>,
                 stringsAsFactors <span class='op'>=</span> <span class='cn'>FALSE</span><span class='op'>)</span>

<span class='va'>DS</span> <span class='op'>&lt;-</span> <span class='fu'><a href='https://rdrr.io/r/base/data.frame.html'>data.frame</a></span><span class='op'>(</span>USUBJID <span class='op'>=</span> <span class='fu'><a href='https://rdrr.io/r/base/c.html'>c</a><