http://www.perlmonks.org?node_id=464235


in reply to Complex Data Structure Suggestions Wanted

You don't have to check for existence. You can just use an undefined value as an arrayref and it will autovivify: 
    foreach my $ItemID (@Data){ 
        push @{$$HashRef{$ItemID}}, $DataSource;
# The usual preferred notation is
#       push @{$HashRef->{$ItemID}}, $DataSource;
    }

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Re^2: Complex Data Structure Suggestions Wanted
by Ninthwave (Chaplain) on Jun 07, 2005 at 12:19 UTC

    Thank you, I prefer the preferred notation nice to agree with the masses for a change.

    "No matter where you go, there you are." BB
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