t sourceCode r">
<code class="sourceCode R"><span><span class="va">m</span></span>
<span><span class="co">#&gt;       John Paul George Ringo</span></span>
<span><span class="co">#&gt; duck     1    2      3     4</span></span>
<span><span class="co">#&gt; duck     5    6      7     8</span></span>
<span><span class="co">#&gt; goose    9   10     11    12</span></span>
<span><span class="fu"><a href="../reference/aggregate_byname.html">aggregate_byname</a></span><span class="op">(</span><span class="va">m</s