sub hash-join(@a, &a, @b, &b) {
my %hash := @b.classify(&b);
@a.map: -> $a {
|(%hash{$a.&a} // next).map: -> $b { [$a, $b] }
}
}
my @A =
[27, "Jonah"],
[18, "Alan"],
[28, "Glory"],
[18, "Popeye"],
[28, "Alan"],
;
my @B =
["Jonah", "Whales"],
["Jonah", "Spiders"],
["Alan", "Ghosts"],
["Alan", "Zombies"],
["Glory", "Buffy"],
;
.say for hash-join @A, *[1], @B, *[0];
[[27 Jonah] [Jonah Whales]]
[[27 Jonah] [Jonah Spiders]]
[[18 Alan] [Alan Ghosts]]
[[18 Alan] [Alan Zombies]]
[[28 Glory] [Glory Buffy]]
[[28 Alan] [Alan Ghosts]]
[[28 Alan] [Alan Zombies]]