First unique char

sub first-unique-char(Str $str) {
    my @str = $str.comb;
    do given @str.grep(* ne " ").Bag -> %chars {
        @str.first: { %chars{$_} == 1 }, :k
    }
}

say first-unique-char "Perl Weekly Challenge";
say first-unique-char "Long Live Perl"