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

Hello,

I have a three dimensional hash with info like below.

%LPAR_config = (
                 'lpar1' => {
                                            'profile1' => { ...
                                                          },
                                            'profile2' => { ...
                                                          },
                                            'frame' => 'frame1',
                                            'lpar_id' => '1'
                           }
                'lpar2' => {
                                            'profile1' => { ...
                                                          },
                                            'profile2' => { ...
                                                          },
                                            'frame' => 'frame1',
                                            'lpar_id' => '2'
                'lpar3' => {
                                            'profile1' => { ...
                                                          },
                                            'profile2' => { ...
                                                          },
                                            'frame' => 'frame2',
                                            'lpar_id' => '1'
                           }
                'lpar4' => {
                                            'profile1' => { ...
                                                          },
                                            'profile2' => { ...
                                                          },
                                            'frame' => 'frame2',
                                            'lpar_id' => '2'

...
)

[download]

I've skipped the original list, as it has 191 lpars and each a lot of info. At one point in the program I need to get the name of the lpar from frame2 with lpar_id 1.

I'm now looping trough the keys to check if the lpar with name $key is on frame "frame2" and has lpar_id 1.
As I can skip most of the entries I was wondering, is there an easier way to get the key based on the content of the values of $key

On a related note, is there an easy way (read without looping myself) to copy a subset of the hash (for example all lpars on frame2) to another hash? This would speed-up the script, as most data is needed of just 1 frame (of 14 available)

Replies are listed 'Best First'.
Re: Easy way to find data in hash or get subset of hash
by roboticus (Chancellor) on Mar 05, 2013 at 15:42 UTC

    T_I:

    I'm probably misunderstanding your question, but is this what you're asking for?

    if (! exists $LPAR_config{$key}) {
  die "We don't have $key!\n";
}
if ($LPAR_config{$key}{frame} eq "frame2"
    and $LPAR_config{$key}{lpar_id} == 1) {
  print "Found it!\n";
}

    [download]

    ...roboticus

    When your only tool is a hammer, all problems look like your thumb.

[reply]
[d/l]
Re: Easy way to find data in hash or get subset of hash
by Athanasius (Archbishop) on Mar 05, 2013 at 15:49 UTC

    To avoid the loop, put the conditions given by roboticus, above, into the block of a grep:

    #! perl
use strict;
use warnings;
use Data::Dump;

my %LPAR_config =
(
    lpar1 =>
    {
        profile1 => {},
        profile2 => {},
        frame    => 'frame1',
        lpar_id  => '1',
    },

    lpar2 =>
    {
        profile1 => {},
        profile2 => {},
        frame    => 'frame1',
        lpar_id  => '2',
    },

    lpar3 =>
    {
        profile1 => {},
        profile2 => {},
        frame    => 'frame2',
        lpar_id  => '1'
    },

    lpar4 =>
    {
        profile1 => {},
        profile2 => {},
        frame    => 'frame2',
        lpar_id  => '2',
    },
);

my @matches = grep { $LPAR_config{$_}->{frame  } eq 'frame2' &&
                     $LPAR_config{$_}->{lpar_id} eq '1' } keys %LPAR_c
+onfig;
dd @matches;

    [download]

    Output:

     1:43 >perl 560_SoPW.pl
"lpar3"

 1:44 >

    [download]

    Hope that helps,

    Athanasius <°(((>< contra mundum Iustus alius egestas vitae, eros Piratica,

[reply]
[d/l]
[select]

      Thanks, that helped a lot. It's easy readable and maintainable.

[reply]
Re: Easy way to find data in hash or get subset of hash
by Anonymous Monk on Mar 05, 2013 at 15:33 UTC

    As I can skip most of the entries I was wondering, is there an easier way to get the key based on the content of the values of $key

    Easier than what?

    See Data::Diver

    On a related note, is there an easy way (read without looping myself) to copy a subset of the hash (for example all lpars on frame2) to another hash? This would speed-up the script, as most data is needed of just 1 frame (of 14 available)

    Yes, write a function, then call it as many times as you want --- the function does the looping, so you don't have to repeat it yourself -- see Data::Visitor::Callback

[reply]

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