As perlplexer points out $modifiedFiles is a HASH ref not an ARRAY ref thus the code you post is not the cause of your troubles. You wish to check if a HASH KEY exists, and here is how you do it (you need the defined otherwise the key can exist but have a value of '' or 0 which will be false). unless(blah) is the same as if(! blah)

my $hash_ref = {};
unless ( defined $hash_ref->{'some_key'}) {
    print "some_key is not defined\n";
}

my $other_hash_ref = { 'some_key' => 0 };
if ( ! defined $other_hash_ref->{'some_key'}) {
    print "some_key is not defined\n";
} else {
    print "some_key is defined\n";
}
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cheers

tachyon

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