"I want to get just the values of each child for a certain parent"

"How do I get the key values for the first branch (parent id) of the hash?"

Note that the values for each key for parents is actually a reference and so is the value for each child key(a, b, c) in this data structure... If you meant by values that you want the IDs for each child of a certain parent, as I understood, then I hope the following excerpt of code can be of help.

#!/usr/local/bin/perl
use strict;
use warnings;

my %children;
#each parent has 3 children identified by their IDs
$children{'parent1'}{'a'}{'id'} = 'Child1P1';
$children{'parent1'}{'b'}{'id'} = 'Child2P1';
$children{'parent1'}{'c'}{'id'} = 'Child3P1';
$children{'parent2'}{'a'}{'id'} = 'Child1P2';
$children{'parent2'}{'b'}{'id'} = 'Child2P2';
$children{'parent2'}{'c'}{'id'} = 'Child3P2';


for my $parent (sort keys (%children)){
    print "The key value is a reference of type: ", ref $children{$par
+ent}, $/;
    print "The parent is $parent:\n";
    for my $child (keys (%{$children{$parent}})){
           print "children of $parent-> $children{$parent}{$child}{'id
+'}\n";
           }
        print "\n\n";
    }
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#OUTPUT:

The key value is a reference of type: HASH
The parent is parent1:
children of parent1-> Child3P1
children of parent1-> Child1P1
children of parent1-> Child2P1


The key value is a reference of type: HASH
The parent is parent2:
children of parent2-> Child3P2
children of parent2-> Child1P2
children of parent2-> Child2P2
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