CODEWITHSUNDEEP
perlhashhashmaphashtable
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Reputation: 3165

perl how to delete the top level/primary hash key including its values for a hash of hash

I have a hash of hash value I am getting from a subroutine. Pasting the code chunk below.

sub check_interfaces()
my @interfaces = IO::Interface::Simple->interfaces;
my ($ip, $subnet, $dscp) = @_;
my %check_config = (
    "ip" => $ip,
    "subnet" => $subnet,
    "dscp" => $dscp
);

foreach my $if (@interfaces) {
    if (not defined $if->address) {
        next;
    }
    %check_configs = ( config => \%check_config );
    my %interface = ($if, $if->address);
    if ($check_configs{config}{ip} && $check_configs{config}{ip} =~ /$interface{$if}/) {
        print "$check_configs{config}{ip} already configured\n\n";
        delete $check_configs{config}{ip};
        delete $check_configs{config}{subnet};
        delete $check_configs{config}{dscp};
        delete $check_configs{config};
    }
}
print Dumper %check_configs;

This is giving me output as

root@server:/l3dsr# perl test.pl start
10.75.21.23 already configured

$VAR1 = 'config';
$VAR2 = {};
$VAR1 = 'config';
$VAR2 = {
      'dscp' => '2',
      'ip' => '10.75.130.24',
      'subnet' => '255.255.255.255'
    };

I was trying to delete the primary hash key, but it was not getting deleted. If I am not deleting, the output would be

10.75.21.23 already configured

$VAR1 = 'config';
$VAR2 = {
      'dscp' => '2',
      'ip' => '10.75.21.23',
      'subnet' => '255.255.255.255'
    };
$VAR1 = 'config';
$VAR2 = {
      'dscp' => '2',
      'ip' => '10.75.130.24',
      'subnet' => '255.255.255.255'
    };

What I am trying to do is to get rid of this chunk of hash of hash

$VAR1 = 'config';
$VAR2 = {
      'dscp' => '2',
      'ip' => '10.75.21.23',
      'subnet' => '255.255.255.255'
    };

by doing 

            delete $check_configs{config}{ip};
            delete $check_configs{config}{subnet};
            delete $check_configs{config}{dscp};
            delete $check_configs{config};

But it is not working as expected. What am I doing wrong here?

Added Dumper just after the delete, but there is nothing being printed. However, I am printing the keys, and you can see the duplicate occurrence of the key here.

    if ($check_configs{config}{ip} && $check_configs{config}{ip} =~ /$interface{$if}/) {
        print "$check_configs{config}{ip} already configured\n\n";
        delete $check_configs{config}{ip};
        delete $check_configs{config}{subnet};
        delete $check_configs{config}{dscp};
        delete $check_configs{config};
        print Dumper %check_configs;
    }
}
print keys %check_configs;

Output::

root@server:/l3dsr# perl test.pl start
10.75.21.23 already configured

configconfigroot@server:/l3dsr#

Borodin: With 

$Data::Dumper::Useqq = 1;
print Dumper [ keys %check_configs ];

Output::

root@cdn-fe13:/l3dsr# perl test.pl start
10.75.21.23 already configured

$VAR1 = [
      "config"
    ];
$VAR1 = {
      "config" => {}
    };
$VAR1 = [
      "config"
    ];
$VAR1 = {
      "config" => {
                    "dscp" => 2,
                    "ip" => "10.75.130.24",
                    "subnet" => "255.255.255.255"
                  }
    };

Update::

If I add a delete after the delete $check_configs like

            delete $check_configs{config}{subnet};
            delete $check_configs{config}{dscp};
            delete $check_configs{config};
        }
    }
    if (!keys $check_configs{config}) {
        delete $check_configs{config};
    }
    print  keys %check_configs ;

it deletes the empty config keys. However, if I add it above, as 

    if (!keys $check_configs{config}) {
        delete $check_configs{config};
    }
    if ($check_configs{config}{ip} && $check_configs{config}{ip} =~ /$interface{$if}/) {....

it is not working. I am not sure where it is getting the empty keys from.

Upvotes: 1

Views: 256

Answers (1)

nohup
nohup

Reputation: 3165

Worked with the following code.

        delete $check_configs{config}{subnet};
        delete $check_configs{config}{dscp};
        delete $check_configs{config};
        }
}
if (!keys $check_configs{config}) {
        delete $check_configs{config};
        }
print  keys %check_configs ;

Upvotes: 2

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