In this contrived little example, I'm matching any "a" preceded by a "c" and any "t" preceded by a "k": 
$_ = "caaat";
my @hits = m/(?:c(a)|k(t))/g;
foreach (@hits) { print "|$_|\n" }

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It produces two hits - an "a" and an empty string. Yet if both conditions fail (by changing $_ to "zzzzz"), it produces no hits, as expected. Why the empty string? And can I avoid it, other than by post-processing @hits? Thanks!

In reply to empty hits with regex by Anonymous Monk

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