">c</a></span><span class="op">(</span><span class="st">"a"</span>, <span class="st">"b"</span>, <span class="st">"c"</span>, <span class="st">"d"</span><span class="op">)</span>,</span>
<span>  x <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="fl">1</span>,   <span class="fl">2</span>,   <span class="fl">3</span>,   <span class="fl">4</span>  <span class="op">)</span>,</span>
<span>  y <span class