The idea strike to my mind when I encounter this 
use Data::Dumper;
$hash{keya} ;
$hash{keyb} ;
$hash{keyc} ;

$hash{keya}{1} = "fooA";
$hash{keya}{2} = "barA";
$hash{keyb}{1} = "fooB";
$hash{keyb}{2} = "barB";
$hash{keyc}{1} = "fooC";
$hash{keyc}{2} = "barC";

print Dumper (\%hash);

__output__

$VAR1 = {
          'keya' => {
                      '1' => 'fooA',
                      '2' => 'barA'
                    },
          'keyb' => {
                      '1' => 'fooB',
                      '2' => 'barB'
                    },
          'keyc' => {
                      '1' => 'fooC',
                      '2' => 'barC'
                    }
        };

[download]
Let this is case 1. I assigned 2 values to each key (keya, keyb, keyc). Note that $hash{keya}{1} also a hash itself, so I supposed $hash{keya} is pointed to an array of pointers, which in turn pointed to $hash{keya}{1} and $hash{keyb}{2} respectively. And $hash{keya}{1} pointed to value "fooA" ultimately.
However, in case 2, which I initialize hash like this: 
use Data::Dumper;
$hash{keya} = "";
$hash{keyb} = "";
$hash{keyc} = "";

$hash{keya}{1} = "fooA";
$hash{keya}{2} = "barA";
$hash{keyb}{1} = "fooB";
$hash{keyb}{2} = "barB";
$hash{keyc}{1} = "fooC";
$hash{keyc}{2} = "barC";

print Dumper (\%hash);

__output__

$VAR1 = {
          'keya' => '',
          'keyb' => '',
          'keyc' => ''
        };

[download]
As you notice $hash (keya, keyb, keyc) is as its initialize value, not pointed to each {1} and {2} repectively. $hash{keya}{1} is still exist if you print it out. But $hash{keya} cannot access $hash{keya}{1} anymore.
Hence I deduced that hash is an array of pointer. ^_^, up to here, I have no concrete evidence or proof, that why I put up my query here to ask for advice. Hope can share with you guys.
Regards,
donno20 ^_^

In reply to Re: Re: Hash and Array by donno20
in thread Hash and Array by donno20

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