 by reference operations performed on the copied object will not affect the original object.</p>
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<div id="section-13" class="section level1">
<h1></h1>
<p>There are two particular places where <code>copy()</code> function is essential:</p>
<ol style="list-style-type: decimal">
<li><p>Contrary to the situation we have seen in the previous point, we may not want the input data.table to a function to be modified <em>by reference</em>. As an example, let’s consider the task in the 