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Re^5: Nested Data Structures for Dummies?

by GrandFather (Cardinal)
on Apr 15, 2010 at 04:17 UTC ( #834826=note: print w/ replies, xml ) Need Help??


in reply to Re^4: Nested Data Structures for Dummies?
in thread Nested Data Structures for Dummies?

So what do you want to do with it? I'd be inclined to turn it into an object then write a few accessor methods to pull out interesting fragments. Consider:

use strict; use warnings; my %hash = ( 'some item' => { 'source' => 'a source', 'conversions' => { 'conversion 1' => 'value 1', 'conversion 2' => 'value 2', 'conversion 3' => 'value 3', 'conversion 4' => 'value 4', 'conversion 5' => 'value 5', }, 'whatever' => 'eh', }, 'another item' => { 'source' => 'another source', 'conversions' => { 'conversion 1' => 'value 1', 'conversion 2' => 'value 2', }, 'whatever' => 'eh', }, 'one more item' => { 'source' => 'another source', 'whatever' => 'eh', }, ); my $obj = bless {data => \%hash}; for my $item ($obj->getItems ()) { print "$item->{name}: $item->{source}, $item->{whatever}\n"; } my %conversions = $obj->getConversions ('some item'); print "$_ => $conversions{$_}\n" for sort keys %conversions; sub getItems { my ($self) = @_; my $data = $self->{data}; return map {{name => $_, %{$data->{$_}}}} keys %$data; } sub getItem { my ($self, $itemName) = @_; return if ! exists $self->{data}{$itemName}; return $self->{data}{$itemName}; } sub getConversions { my ($self, $itemName) = @_; return if ! exists $self->{data}{$itemName}; my $item = $self->{data}{$itemName}; return if ! exists $item->{conversions}; return %{$item->{conversions}}; }

Prints:

some item: a source, eh another item: another source, eh one more item: another source, eh conversion 1 => value 1 conversion 2 => value 2 conversion 3 => value 3 conversion 4 => value 4 conversion 5 => value 5

Such an approach is worth doing if your data structure has a consistent structure and you need to perform a bunch of queries against it. If the data is not consistently structured then it's going to be endless hard work no matter what because you simply have to deal with special cases and that is always a source of pain.

Note that I fixed a bunch of syntax errors in the structure you gave so I presume that your sample doesn't map on to anything real in any sense.

True laziness is hard work


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Re^6: Nested Data Structures for Dummies?
by jedikaiti (Friar) on Apr 15, 2010 at 16:31 UTC

    Yea, it's a very generalized form of the actual structure I have. The part that's giving me a headache at the moment is getting the conversions out, one at a time.

    Going to go through your code right now. Thank you!

    Kaiti
    Swiss Army Nerd

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