_len</a></span>(<span class='fu'><a href='https://rdrr.io/r/base/nrow.html'>nrow</a></span>(<span class='no'>flights</span>))
<span class='no'>flights</span>$<span class='no'>stroke</span> <span class='kw'>&lt;-</span> <span class='fu'><a href='https://rdrr.io/r/base/sample.html'>sample</a></span>(<span class='fl'>1</span>:<span class='fl'>3</span>, <span class='kw'>size</span> <span class='kw'>=</span> <span class='fu'><a href='https://rdrr.io/r/base/nrow.html'>nrow</a></span>(<span class='no'>flights</spa