Cody Fendant has asked for the wisdom of the Perl Monks concerning the following question:
Inspired by the fact that 2013 is the first year since 1987 which has four unique digits, what's your best code to determine the number of unique digits in a number?
Here's what I ended up with, skipping the %unique method:
$y = 2013; ($y = join('',sort(split(//,$y)))) =~ tr/0-9//s; print "unique digits: " . length($y) . $/;
I'm sure there's something smarter.