my @some-numbers = 3, 1, 4, 1, 5, 9, 2, 6; my @to-match = 9, 7, 1, 2, 1, 1; my @matched; my %histogram; for @some-numbers -> $n { %histogram{$n}++ }; for @to-match -> $n { next if not defined %histogram{$n}; if %histogram{$n} > 0 { push @matched, $n; %histogram{$n}--; } }; say @matched;