Consider...
for %addrbook.classify({ .value.substr(0,1).uc }).sort -> $g { say "{$g.key}:"; .say for $g.value».invert».fmt(" %-32s %s"); }
So, the outer loop iterates over the sorted pairs, passing each to $g in the block.
( "A" => ["allison\@parrot.org" => "Allison Randal", "audreyt\@audreyt.org" => "Audrey Tang"], "J" => ["jnthn\@jnthn.net" => "Jonathan Worthington", "jesse\@fsck.org" => "Jesse Vincent"], "L" => ["larry\@wall.org" => "Larry Wall"], "P" => ["pmichaud\@pobox.com" => "Patrick R. Michaud"] )continued...