This uses a hash as hashslice, and so sets the values of the keys contained by @nocapslist to undef. I'd prefer
@nocapslist{ @nocapslist } = ();
because in my eyes, undef is a scalar value...

But it's just a matter of different tastes ;-)

Best regards,
perl -e "print a|r,p|d=>b|p=>chr 3**2 .7=>t and t"