="co">#&gt; 76874: MCID3112800920  20101 240102</span></span>
<span><span class="co">#&gt; 76875: MCID3112870009  19951 240102</span></span></code></pre></div>
<p><em>Filter.</em>   Remove unnecessary variables and filter for unique
observations.</p>
<div class="sourceCode" id="cb8"><pre class="downlit sourceCode r">
<code class="sourceCode R"><span><span class="co"># Unique combinations of ID and CIP</span></span>
<span><span class="va">DT</span> <span class="op">&lt;-</span> <span class="va">DT</span><sp