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Old 03-03-2014, 06:03 AM   #1
Ramurd
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Registered: Mar 2009
Location: Rotterdam, the Netherlands
Distribution: Slackwarelinux
Posts: 561

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perl - Array logic


I have this database, where some logging is stored; This is in 'domainnm', 'container', 'item' and 'value';

This data is queried with my perl script and where I keep stumbling is this issue:
Per container there are two entries for 'item' (it's about memory usage, btw - to keep talk easier): one is CurrentUsage, the other MaxUsage (which is the maximum of memory allocated since running).

So I thought to fetch the results in an array. (fetchall_arrayref({} fyi), and then iterate over this array and create a smart hash. Only, I am lacking in the "smart" department today, sorely lacking.

This is what I came up with:

Code:
sub parse_results($)
{
        my $results=shift;

        my %onehash;
        my $itemkey;

        for my $row(@$results)
        {
                for my $field(keys %$row)
                {
                        if($row->{'item'} eq 'CurrentUsage')
                        {
                                $itemkey='current_usage';
                        }
                        elsif($row->{'item'} eq 'MaxUsage')
                        {

                                $itemkey='max_usage';
                        }
                        else
                        {
                                $itemkey=$row->{'item'};
                        }
                        %onehash->{$row->{'container'}} = (
                                $itemkey=>$row->{'value'}
                                );
                }
        }
        print Dumper(\%onehash);
}
This is plainly not doing what I want; I was thinking of a hash (or array, whatever) with fields like this:
container | current_usage | max_usage
Container1 | 12345 | 123456
Container2 | 54321 | 654321
... etc

What am I doing wrong? Perl complains: Using a hash as a reference is deprecated, and Useless use of a constant in void context and Useless use of hash element in void context etc...
 
Old 03-03-2014, 07:11 AM   #2
Ramurd
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Registered: Mar 2009
Location: Rotterdam, the Netherlands
Distribution: Slackwarelinux
Posts: 561

Original Poster
Rep: Reputation: 76
I should've lunched sooner... I think this is getting a bit closer (at least), might even be 'the' answer:

Code:
                        %onehash->{$row->{'container'}} = (
                                $itemkey=>$row->{'value'}
                                );
is now rewritten as:
Code:
                        $onehash{$row->{'container'}}->{$itemkey} = $row->{'value'};
This seems to yield the correct results.
 
  


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