On Wed, 2006-07-06 at 07:49 -0500, Ron Goral wrote:
> Merely referencing a key in a hash sets it into the hash, though with a
> value of undef.

No, it does not. You have to actually assign it a value for the key to
appear. The value you assign it may be undef, but Data::Dumper will only
show the key if it has been assign a value.

The confusion arises because an expression like: $self->{file} may be
undef because:

1. There is no such key 'file' in the hash.

Or

2. The key is in the hash but set to undef.

To remove a key from a hash, you must use delete. See `perldoc -f
delete`.


-- 
__END__

Just my 0.00000002 million dollars worth,
   --- Shawn

"For the things we have to learn before we can do them, we learn by doing them."
  Aristotle

* Perl tutorials at http://perlmonks.org/?node=Tutorials
* A searchable perldoc is at http://perldoc.perl.org/



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