my %hash = (foo => 42, bar => 84);

# Here is the easiest way:
my @kv_pairs = %hash
print "All keys and all values as a flattened list: ", @kv_pairs, "\n";

# Ok, an even easier way:
print "All keys and all values as a flattened list: ", %hash, "\n"; # Because, list context.

# Here is another way:
while (my ($key, $value) = each %hash) {
    print "$key => $value\n";
}

# Here is another way:
my @keys = keys %hash;
my @values = values %hash;
for my $i (0.. $#keys) { # (fixed)
    print "$keys[$i] => $values[$i]\n";
}

# And yet another:
foreach my $key (keys %hash) {
    print "$key => $hash{$key}\n";
}