my $value = $hashdata{$key};
my @array = @$value;       # The whole array.
my $first = $value->[0];   # The first element.
my $last  = $value->[-1];  # The last element.
[download]

$value is an array reference. To get to the array, we need to de-reference it.

Seems like you should read perlref and perlreftut.