##
$len = length($_);
#let's say $len is 5
$hash{$len}=[] unless defined $hash{$len};
# make a hash key called "5" with an empty array as the value
push($hash{$len},$_);
#use it as an array and push this five-letter word onto it.
##
##
($_='jjjuuusssttt annootthhrer
pppeeerrrlll haaaccckkeer')=~y/a-z//s;print;