restrict the population of elements in a data structure.

[babp]

Hi All,
Please help me to restrict the population of this hash structure.I don't want to exit from the program if var not defined on this example.

#!/usr/bin/perl
my %a;
if (defined $a{'abd'}->[0] ){
print "yes \n";

}
use Data::Dumper;
print Dumper \%a;
RESULT
======

$VAR1 = {
          'abd' => []
        };

Objective is to restrict automatic creation of this structure on validation.

[RonB]

First check to see if the hash key exists, then, if needed, test if it's defined.