my @items = (
    ["foo", 1],
    ["bar", 3],
    ["baz", 4],
    ["quux", 9]
);

##</code><code>##

  use List::Util;
  my $total_weight = List::Util::sum(map { $_->[1] } @items);

##</code><code>##

  my $pick = int(rand($total_weight));
  my $picked_item = (List::Util::first { $pick -= $_->[1]; $pick < 0 } @items)->[0];