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

my @nodes = qw/foo quux baz/;
my %HoH = (
    foo => { day => 'Mon' },
    bar => { day => 'Tue' },
    baz => { day => 'Wed' }
);

# Loop over nodes
for my $node (@nodes) {
    if (exists $HoH{$node}) {
        print "Node $node found in HoH and deleted\n";
        # Do more processing here
        delete $HoH{$node};
    } else {
        print "Node $node not found in HoH\n";
    }
}

# Loop over remaining unmatched keys
for my $key (keys %HoH) {
    print "Key $key with payload $HoH{$key}->{day} not matched, so added\n";
}