fu"><a href="https://rdrr.io/r/base/colnames.html" class="external-link">rownames</a></span><span class="op">(</span><span class="va">mtcars</span><span class="op">)</span>, <span class="kw">function</span><span class="op">(</span><span class="va">x</span><span class="op">)</span> <span class="fu"><a href="https://rdrr.io/r/base/strsplit.html" class="external-link">strsplit</a></span><span class="op">(</span><span class="va">x</span>, <span class="st">" "</span><span class="op">)</span><span class="op">[[</