n> <span class='kw'>&lt;-</span> <span class='no'>elements</span>$<span class='no'>metal</span>

<span class='co'># make coordinates for labels</span>
<span class='no'>elements</span>$<span class='no'>symx</span> <span class='kw'>&lt;-</span> <span class='fu'><a href='https://rdrr.io/r/base/paste.html'>paste</a></span>(<span class='no'>elements</span>$<span class='no'>group</span>, <span class='st'>":0.1"</span>, <span class='kw'>sep</span> <span class='kw'>=</span> <span class='st'>""</span>)
<span class='