First of all, you should probably add a 'use strict;' at the top of your code. It will show you a couple of problems with the code you presented above.

Second, if you are having problems with data structures, and they are not doing what you want, use Data::Dumper to see what is actually happening. Add the following code snippet after you have built your data structure:

use Data::Dumper;
print Dumper(\%newhash);
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When I ran your code with this, it gave me the following:

$VAR1 = {
          'IP' => [
                    'value1',
                    'value2',
                    'value1',
                    'value2'
                  ]
        };
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So the code is not doing what think it is doing.

I hope that gives you enough to continue.

- Cees

Thank you very much Cees. After spending a little more time with your explanations, everything works great. David

You are talking about a hash of arrays in your original question, but it looks like you really want an array of arrays... Is this correct?

In your code you have the following:

push (@{%newhash->{$rows[0]}}, @newrows);
push (@{%newhash->{$rows[0]}}, @newrows);
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We can simplify this to the following since $rows[0] = 'IP' and does not change (Do you maybe want a real IP address here?):

push @{$newhash{IP}}, @newrows);
push @{$newhash{IP}}, @newrows);
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Which is essentially saying that you want to treat the value at $newhash{IP} as an array reference, and you want to push the values in @newrows onto the end that array.

If you want this to be a two dimensional array, then you need to take Paladin's advice and push a reference to the array instead of pushing the values of the array.

push @{$newhash{IP}}, [@newrows]);
push @{$newhash{IP}}, [@newrows]);
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That will make copies of the array, and push a reference to the new array (you could also use \@newrows). Using Data::Dumper, the above will show up as:

$VAR1 = {
          'IP' => [
                    [
                      'value1',
                      'value2'
                    ],
                    [
                      'value1',
                      'value2'
                    ]
                  ]
        };
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Is this what you are after?

Now the loop at the end where you are trying to read the values will require some changes as well:

@printrows = $newhash{$key}; # wrong -> the hash will contain a refere
+nce to an array
@printrows = @{$newhash{$key}}; # right -> de-reference the array firs
+t
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After those changes, your code prints what you seem to be asking for. Although I am still not 100% sure this is what you are really after...

- Cees