SPUG: Slice of HashOfHash

[Colin Meyer]

On Wed, Nov 15, 2006 at 04:39:23PM -0800, Juan Jose Natera wrote:
> On the other hand, if you do need to keep a copy of the results:
> 
> my %matched = map { $_ => $HoH{$_} } grep { $HoH{$_}->{husband} eq
> 'fred' } keys %HoH;

It is worth noting that the "copy" contains the same references as the
original, so that any modifications to the subhashes in the copy also
show up in the original. If you need a deep copy, try a slight
modification:

    use Storable 'dclone';
    my %matched = map { $_ => dclone( $HoH{$_} ) } 
        grep { $HoH{$_}->{husband} eq 'fred' } keys %HoH;

-Colin.