Retrieving a list of keys from a hash of hashes

Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

From the foolowing data structure, how can I retrieve a list of keys?

$VAR1 = '0x10040';
$VAR2 = {
          '' => {},
          'ZoomScale' => {
                           'Flags' => 'R,W,D',
                           'Id' => '0x11b2c',
                           'Type' => 'Integer',
                           'Name' => 'ZoomScale'
                         },
          'Model_State' => {
                             'Flags' => 'R,W,M,D',
                             'Id' => '0x1007c',
                             'Type' => 'Integer',
                             'Name' => 'Model_State'
                           },
          'View_Description_List' => {
                                       'Flags' => 'R,W,D',
                                       'Id' => '0x11f48',
                                       'Type' => 'Tagged Octet',
                                       'Name' => 'View_Description_Lis
+t'
                                     },
          'mdl_modfy_athr' => {
                                'Flags' => 'R,W,D',
                                'Id' => '0x11025',
                                'Type' => 'Text String',
                                'Name' => 'mdl_modfy_athr'
                              },
          'IfOrgRel' => {
                          'Flags' => 'R,W,S,D',
                          'Id' => '0x11b4d',
                          'Type' => 'Relation Handle',
                          'Name' => 'IfOrgRel'
                        },
          'Collected_By_List' => {
                                   'Flags' => 'R,W,M,D',
                                   'Id' => '0x10c48',
                                   'Type' => 'Octet String',
                                   'Name' => 'Collected_By_List'
                                 },
          'createtime' => {
                            'Flags' => 'R,D',
                            'Id' => '0x11b41',
                            'Type' => 'Date',
                            'Name' => 'createtime'
                          },
          'Is_Device' => {
                           'Flags' => 'R,W,S,D',
                           'Id' => '0x11f4a',
                           'Type' => 'Boolean',
                           'Name' => 'Is_Device'
                         },
          'Rollup_Condition' => {
                                  'Flags' => 'R,W,G,M',
                                  'Id' => '0x10013',
                                  'Type' => 'Integer',
                                  'Name' => 'Rollup_Condition'
                                },
[download]

I'm trying to populate an array with the following keys:

ZoomScale
model_State
View_Description_List
.
.
.
[download]

Comment on Retrieving a list of keys from a hash of hashes Select or Download Code

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Re: Retrieving a list of keys from a hash of hashes by broquaint (Abbot) on Apr 01, 2003 at 14:14 UTC
/me suggests `my @keys = keys %{ $hash{'0x10040'} };` [download] See. `perlreftut` for more info. HTH `_________ broquaint`	[reply] [d/l]
Re: Retrieving a list of keys from a hash of hashes by robartes (Priest) on Apr 01, 2003 at 14:15 UTC
To get the list of keys of the hash pointed to by $VAR2, you dereference the hashref: `my @keys = keys %$VAR2;` [download] The same goes for getting the keys of a next level hash: dereference the hashref, which in this case happens to be a hash value as well: `my @keys2 = keys %{$VAR2->{'Model_State'}};` [download] For more information, have a look at perlreftut, perlref and perldsc. Update: Ugh, this was output from Data::Dumper::Dumper of a hash. ~~BrowserUK~~ broquaint spotted this well. His solution is probably a direct plug in for your program. CU Robartes-	[reply] [d/l] [select]
Re: Retrieving a list of keys from a hash of hashes by zby (Vicar) on Apr 01, 2003 at 14:21 UTC
So you say it is just one hash. I gues you write it down with code simmilar to `print Dumper(%yourhash)`. Then you can get the list with `keys %{$yourhash{'0x10040'}}`.	[reply] [d/l] [select]