pan><span class='op'>[</span>, <span class='fu'><a href='https://rdrr.io/r/base/names.html'>names</a></span><span class='op'>(</span><span class='va'>x</span><span class='op'>$</span><span class='va'>data</span><span class='op'>)</span> <span class='op'>%in%</span> <span class='va'>asserts</span><span class='op'>$</span><span class='va'>name</span><span class='op'>]</span>
 <span class='fu'><a href='https://rdrr.io/r/base/which.html'>which</a></span><span class='op'>(</span><span class='fu'><a href='https:/