m> copies R does.</p>
<div id="shallow-vs-deep-copy" class="section level4 bs-callout bs-callout-info">
<h4 class="bs-callout bs-callout-info"><em>shallow</em> vs <em>deep</em> copy</h4>
<p>A <em>shallow</em> copy is just a copy of the vector of column pointers (corresponding to the columns in a <em>data.frame</em> or <em>data.table</em>). The actual data is not physically copied in memory.</p>
<p>A <em>deep</em> copy on the other hand copies the entire data to another location in memory.</p>
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