my @filtered = grep { .[0] ne .[1] }, do [ $0, $1 ] while $s ~~ m:g[(.)(.)]; my @filtered = do [ $0, $1 ] if $0 ne $1 while $s ~~ m:g[(.)(.)]; my @filtered = ([ $0, $1 ] if $0 ne $1 for $s.comb(/(.)(.)/)); my @filtered = map -> $a, $b {[ $a, $b ] if $a ne $b }, $s.comb;