use strict;
use warnings;

my %hash = ( abc => 123 );

my $abc = exists $hash{abc} ? $hash{abc} : 0;

my $xyz = exists $hash{xyz} ? $hash{xyz} : 0;

print "ABC = $abc : XYZ = $xyz\n";

##</code><code>##

ABC = 123 : XYZ = 0

##</code><code>##

my $vxdg = exists $vxdgs{$node}{$disk} ? $vxdgs{$node}{$disk} : "";