Maybe you still haven't explained the problem correctly. When I undef a hash slice, only one of the values becomes undefined, and when I undef an array slice, only the last element becomes undefined. 
use Data::Dumper;

my @a = qw/a b c d e/;
my %a;
@a{@a} = (1) x @a;

print "--- \@a before ---\n", Dumper \@a;
print "--- \%a before ---\n", Dumper \%a;

undef @a{@a};
undef @a[1,2,3];

print "--- \@a after ---\n", Dumper \@a;
print "--- \%a after ---\n", Dumper \%a;

[download]
Yields this output: 
--- @a before ---
$VAR1 = [
          'a',
          'b',
          'c',
          'd',
          'e'
        ];
--- %a before ---
$VAR1 = {
          'e' => 1,
          'c' => 1,
          'a' => 1,
          'b' => 1,
          'd' => 1
        };
--- @a after ---
$VAR1 = [
          'a',
          'b',
          'c',
          undef,
          'e'
        ];
--- %a after ---
$VAR1 = {
          'e' => undef,
          'c' => 1,
          'a' => 1,
          'b' => 1,
          'd' => 1
        };

[download]

In reply to Re: Hash slice again by lostjimmy
in thread Hash slice again by targetsmart

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