...
%final_data = @loop_data;
...
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What is this line supposed to do?

Please also explain how you intend to use the data stored in %final_data.

Maybe you wanted to use the following construct instead?

return { names => \@loop_data };
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The line %final_data = @loop_data will take the array and map the elements:

my @a = ('H','e','l','o');
my %fus = @a;
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so you will get

%fus:
  H -> e,
  l -> o
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In case you assign an odd list to %final_data the code will break!
What about crating and array of hashes? and return the reference to the array?

Need to store the data in a hash to return from the sub, if Dumper:

$VAR1 = {
          'names' => 'mary',
          'names' => 'john',
          'names' => 'Doe',
          'names  => ''
};
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That's not how hashes work. A key can only appear once in a hash.

Hi, this won't work as you use the same keys.

$VAR1 = {
          'names' => 'mary',
          'names' => 'john',
          'names' => 'Doe',
          'names  => ''
};
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Better try to make an array of hashes which would look like this:

$VAR1 = [
         { 'names' => 'mary'},
         { 'names' => 'john'},
         { 'names' => 'Doe'},
         { 'names  => ''}
];
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or

$VAR1 =  { 'names' => ['mary','john','Doe','']};
];
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