pan class="op">(</span><span class="fu"><a href="https://rdrr.io/r/base/names.html" class="external-link">names</a></span><span class="op">(</span><span class="va">model_data</span><span class="op">)</span><span class="op">)</span></span>
<span>  <span class="co"># remove any NAs</span></span>
<span>  <span class="va">model_data</span><span class="op">[</span><span class="fu"><a href="https://rdrr.io/r/base/NA.html" class="external-link">is.na</a></span><span class="op">(</span><span class="va">model_data</