e number of columns. Code
reproduced from <a href="art-000-getting-started.html#reusable-code">Getting
started</a>.</p>
<div class="sourceCode" id="cb3"><pre class="downlit sourceCode r">
<code class="sourceCode R"><span><span class="co"># Optional. Copy of source files with all variables</span></span>
<span><span class="va">source_student</span> <span class="op">&lt;-</span> <span class="fu"><a href="https://rdrr.io/pkg/data.table/man/copy.html" class="external-link">copy</a></span><span class="op">(</span