rdrr.io/r/base/list.html" class="external-link">list</a></span><span class="op">(</span><span class="cn">NULL</span>,<span class="st">"d"</span><span class="op">)</span><span class="op">)</span></span></span>
<span class="r-in"><span><span class="co"># We also define a match function for lM</span></span></span>
<span class="r-in"><span><span class="va">matchfun</span><span class="op">=</span><span class="kw">function</span><span class="op">(</span><span class="va">d</span><span class="op">)</span><span clas