collection</span>,</span>
<span>  <span class="va">xm</span>,</span>
<span>  <span class="va">ym</span>,</span>
<span>  suffix <span class="op">=</span> <span class="fu"><a href="https://rdrr.io/r/base/c.html" class="external-link">c</a></span><span class="op">(</span><span class="st">"_x"</span>, <span class="st">"_y"</span><span class="op">)</span>,</span>
<span>  fun <span class="op">=</span> <span class="cn">NA</span>,</span>
<span>  <span class="va">...</span></span>
<span><span class="op">)</span></sp