use v6;

my $in = [ 'one', 1, 'two', 2, 'two', '2.003' ];
my %h;

for @($in) -> $k, $v {
    if %h{$k} {
        %h{$k}.push: $v;
    } else {
        %h{$k} = [ $v ];
    }
}

say %h.perl;

# output:
# {"one" => [1], "two" => [2, "2.003"]}