   <span class="va">df</span> <span class="op">&lt;-</span> <span class="fu"><a href="https://rdrr.io/r/base/data.frame.html" class="external-link">data.frame</a></span><span class="op">(</span>a<span class="op">=</span><span class="va">LETTERS</span><span class="op">[</span><span class="fl">1</span><span class="op">:</span><span class="fl">5</span><span class="op">]</span>, b<span class="op">=</span><span class="fl">1</span><span class="op">:</span><span class="fl">5</span><span class="op">)</span>;</span>