o the higher level, for instance using <code>dplyr</code>’s <code>group_by</code> and <code>summarise</code>. Besides the interval, the user can also specify the units. When no unit is specified, a single unit is applied.</p>
<div class="sourceCode" id="cb8"><pre class="sourceCode r"><code class="sourceCode r"><a class="sourceLine" id="cb8-1" data-line-number="1">to_thicken &lt;-<span class="st"> </span><span class="kw"><a href="https://www.rdocumentation.org/packages/base/topics/data.frame">data.frame</a