op">=</span> <span class="fu"><a href="https://rdrr.io/r/base/factor.html" class="external-link">factor</a></span><span class="op">(</span><span class="va">cl4</span><span class="op">)</span>,</span>
<span>    cl5 <span class="op">=</span> <span class="fu"><a href="https://rdrr.io/r/base/factor.html" class="external-link">factor</a></span><span class="op">(</span><span class="va">cl5</span><span class="op">)</span>,</span>
<span>    cl6 <span class="op">=</span> <span class="fu"><a href="https://rdrr.io/r/b