Question

I have this code that works

my @new = keys %h1;
my @old = keys %h2;

function(\@new, \@old);

but can it be done without having to declare variables first?

function must have its arguments as references.

Answer 1

use strict;
use Data::Dumper;

my %test = (key1 => "value",key2 => "value2");
my %test2 = (key3 => "value3",key4 => "value4");

test_sub([keys %test], [keys %test2]);

sub test_sub{
 my $ref_arr = shift;
 my $ref_arr2 = shift;
 print Dumper($ref_arr);
 print Dumper($ref_arr2);
}

Output:

$VAR1 = [
          'key2',
          'key1'
        ];
$VAR1 = [
          'key4',
          'key3'
        ];