Perhaps the Data::Dumper output is a little misleading in this case. I do see an assignment to undef in the source code: 
    elsif (!defined($val)) {
      $out .= "undef";
    }

[download]

Maybe Dumper needs to print out something for non-existent array elements. Maybe it loosely uses 'undef' to mean both undefined and non-existent. If you print the Dumper output before and after your $dow[5] = undef; assignment, they are the same. You can play around with the source code if you really want to get to the bottom of this mystery.

In reply to Re: Exists and arrays (Dumper) by toolic
in thread Exists and arrays by deepakg

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