use Data::Dumper;
my @uris = qw(
   http://www.foo.bar/index.html
   http://www.foo.bar/index.html#foo
   http://www.foo.bar/index.html#bar
);

my %seen;
my @unique_uris = grep !$seen{$_}++, map /^([^?#]+)/, @uris;
print Dumper(\@unique_uris);