What shmem points out is that you're apparently trying to use $_ to refer to 2 separate (distinct) variables, which you can't do.

Samy_rio demonstrated one solution, which is to name the loop variable in each of the loops, so that there isn't a naming conflict.

I wanted to mention an alternative way of viewing the contents of a (possibly complicated) data structure, which is quite commonly used -- Data::Dumper.

For example:

use strict;
use warnings;
use Data::Dumper;

my $data = {
    data => 'hello',
    complicated => {
        version => 1,                                                 
        type => 'struct',
    },
    req => 'Submit'
};

print "Contents of \$data:  ", Dumper($data), "\n";
[download]

which prints:

Contents of $data:  $VAR1 = {
          'req' => 'Submit',
          'complicated' => {
                             'version' => 1,
                             'type' => 'struct'
                           },
          'data' => 'hello'
        };
[download]