Thanks for the response but if you see my code I pasted my code between . I really don't know why are you angry with me ... I am expecting output as device name which I stated in my previous reply. Please don't be angry my apologies. I am able to read my code clearing I don't know why are you saying unreadable mess .... I am again pasting it ...

sub updatedevice() {
my $n = {};

my $Device_LINK = $server->object("ICF_PersistentDataSet",$devicelinks
+);
my $Temp_Device_LINK = $server->object("ICF_PersistentDataSet",$tempde
+vicelinks);

my @current_devicelist = @{ $Device_LINK->invoke("get") };
my @temp_devicelist = @{ $Temp_Device_LINK->invoke("get") };

my %temp_list;
my %current_list;

my $size = @current_list;
for ($n=0; $n < $size; $n++) {
       our $device=$current_list[$n][0];
        DEBUG( "DEBUG: - devicelinks  values $device  " );   
my $size = @temp_list;
for ($n=0; $n < $size; $n++) {
      our $tempdevicelinks=$temp_list[$n][0];
DEBUG( "DEBUG: - temp plc links values $tempdevicelinks " );  
my %count = ();
foreach my $device (@current_list, @temp_devicelist) {
    $count{$device}++;
}
my @difference = grep { $count{$_} == 1 } keys %count;
my @intersect  = grep { $count{$_} == 2 } keys %count;
my @union      = keys %count;

DEBUG( "DEBUG: - difference links values $difference[0] " );
DEBUG( "DEBUG: - intersect links values $intersect[0] " );
DEBUG( "DEBUG: - union links values $union[0] " );

                }
        }
}
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expected output device names Also I am able to read $device and $tempdevicelinks values as "ABC-DCFE41->90" "GHJKL-poiu->78"