&quot;_&quot; in Scala is not a magic variable like in Perl. It&#x27;s a very mechanical syntax transformation, it just expands to &quot;x =&gt; x&quot; (or equivalent, and without colliding with any &quot;x&quot; that&#x27;s already defined).<p>In practice maybe the use is similar. But having a comprehensible theoretical model makes all the difference in terms of making sure you can actually read the code and understand what will happen.