I’m a little surprised no-one has suggested a good, old-fashioned, C-style for loop. If speed is a factor, it’s a clear winner over foreach-with-negation:
use Benchmark qw( cmpthese );
my $n = 1e4;
foreach_loop => \&foreach_loop,
c_for_loop => \&c_for_loop,
for my $i (-$n .. 0)
for (my $j = $n; $j >= 0; --$j)
Output (end only):
Rate foreach_loop c_for_loop
foreach_loop 89.0/s -- -69%
c_for_loop 292/s 227% --
Hope that helps,
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