ss="op">$</span><span class="va">momcol</span> <span class="op">~</span> <span class="st">"F"</span>,</span>
<span>   <span class="va">id</span> <span class="op"><a href="https://rdrr.io/r/base/match.html" class="external-link">%in%</a></span> <span class="va">family</span><span class="op">$</span><span class="va">dadcol</span> <span class="op">~</span> <span class="st">"M"</span>,</span>
<span>   <span class="cn">TRUE</span> <span class="op">~</span> <span class="cn">NA</span><span class="op">)</span><span