I don't think you're on the right track with the hash element not disappearing idea.

There are three possibilities:

1) $last is not defined. Easily verifiable with die("\$last is undef.\n") unless (defined($last));.

2) The key last is not found in %$_ for some element $_ of @{$bros->{$yr}}, as in the following structure:

$bros = {
   '1976' => [
      {
         'first' => 'Eric',
         # oops! no 'last'!
      },
   }
};

[download]

3) $_->{last} is not defined for some element $_ of @{$bros->{$yr}}, as in the following structure:

$bros = {
   '1976' => [
      {
         'first' => 'Eric',
         'last'  => undef,  # oops! no value for 'last'!
      },
   ],
};

[download]

For (2) and (3), printing out $bros or @{$bros->{$yr}} with the help of Data::Dumper might help you locate the record with the missing 'last' or the one which has undef for value.

In reply to Re: Using grep to remove array element from HoAoH leaving empty array-hash element by ikegami
in thread Using grep to remove array element from HoAoH leaving empty array-hash element by Popcorn Dave

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