grep in hash of array

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

Hi Monks,

I want to use grep or map for the following refrence to find the child keys of 'Orange'.

use warnings;
use strict;

my $xml = {
          'Fruits' =>
            [
              {
                'Season' => 
                  { 
                    'Apple' =>
                      {
                        'UnitsAvailable'=> ['100']
                      }, 
                    'Orange' =>
                      { 'UnitsAvailable' => ['200']
                      }
                  }
             }
          ]
 };
[download]

I tried the following code, but it is not finding

my @res = grep (/Orange/,   $xml);
[download]

Please help to find the child keys of Orange.

Thanks
Rose

Comment on grep in hash of array Select or Download Code

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Re: grep in hash of array by Corion (Patriarch) on Aug 05, 2008 at 12:15 UTC
grep does not work that way. grep searches through a list and returns the elements for which a given predicate is true. It seems to me, from the name of your variable, that you would be better served by a different tool, in this case XML::LibXML or XML::XPath or XPath expressions in general.	[reply]
Re^2: grep in hash of array by rose (Beadle) on Aug 05, 2008 at 12:19 UTC
Is it not possible to find without using any module? Thanks Rose	[reply]
Re^3: grep in hash of array by Corion (Patriarch) on Aug 05, 2008 at 12:20 UTC
Of course it is possible to find this out without using any module, because even modules are written in Perl. So, if you want to do this the hard way, you best start learning about data structures via perlreftut and perldsc. Then take a look at Data::Diver and its code. That's it.	[reply]
Re: grep in hash of array by apl (Monsignor) on Aug 05, 2008 at 12:29 UTC
Are you certain that's `$xml` and not `%xml`? In any event, it's your structure. Will you always be looking $key3 in $cml{$key1}{$key2}{Orange}{$key3}? If so, you need three loops. Are you saying Orange can be a key anywhere in the structure? What I'm trying to say (poorly) is that a little more in the way of detail will result in a more focused answer being produced.	[reply] [d/l] [select]
Re^2: grep in hash of array by davorg (Chancellor) on Aug 05, 2008 at 13:51 UTC
Are you certain that's `$xml` and not `%xml`? Why would you want to store a hash reference in a hash? Hash references are usually stored in a scalar, so `$xml` is almost certainly correct :-) -- See the Copyright notice on my home node. "The first rule of Perl club is you do not talk about Perl club." -- Chip Salzenberg	[reply]
Re: grep in hash of array by chakram88 (Pilgrim) on Aug 05, 2008 at 16:50 UTC
I want to use grep or map for the following refrence to find the child keys* of 'Orange'.* My bold emphasis added. `my @o_kids = map { keys %{$xml->{Fruits}[0]{'Season'}{$_}} } grep /orange/i, keys %{$xml->{Fruits}[0]{'Season'}};` Uses all the keywords from your question. But I suspect, as other have mentioned, that you are not asking the right question. Note that this solution requires you to know that (1) Fruits is an array ref (2) Orange is a key to the 'Seasons' hashref, etc. All of which means you have a rather intimate knowledge of the data structure. Unless this is homework in how to use grep, map (and aparently foreach), there is something else you're trying to accomplish.	[reply] [d/l]
Re: grep in hash of array by JavaFan (Canon) on Aug 05, 2008 at 12:45 UTC
For the given example, the following ought to do (but I haven't tested it): `$orange = $$xml{Fruits}[0]{Season}{Orange};` [download] But I suspect that this isn't your real question.	[reply] [d/l]