In Perl $#foo returns the index of the last element. To get the length you use @foo in scalar context. For eg:

    my @bag_of_stuff = qw(do re me fa so la si);

    say $#bag_of_stuff;        # => 6

    say scalar @bag_of_stuff;  # => 7

NB. Lua arrays start at 1. Perl & most other languages start with 0 (zero) index