Does this help?
#!/usr/bin/env perl
use strict;
use warnings;
my %hash = (
key1 => 'value',
key2 => undef,
key3 => {},
key4 => { foo => 99 },
);
foreach my $key (qw(key1 key2 key3 key4)) {
my $reftype = ref ($hash{$key});
if ($reftype && $reftype eq 'HASH') {
my $entries = scalar keys %{$hash{$key}};
print "\$hash{$key} is a hashref which is " .
($entries ? 'not ' : '') . "empty.\n";
} else {
print "\$hash{$key} is not a hashref\n";
}
}
Count the items to see if a hashref is empty or not.
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