)<a class="anchor" aria-label="anchor" href="#nb-and-listw-objects-copied-from-the-nb_igraph-vignette"></a>
</h3>
<p>Since the <strong>spdep</strong> package was created, <em>spatial
weights</em> objects have been constructed as lists with three
components and a few attributes, in old-style class <code>listw</code>
objects. The first component of a <code>listw</code> object is an
<code>nb</code> object, a list of <code>n</code> integer vectors, with
at least a character vector <code>region.id</code> attribu