Create Multi Dimensional Hash Using Array Elements

Question

I need to create multidimensional hashes with varying depth using array elements as keys. Pseudocode attempt:

Example line:

Statement Coverage for instance Hierarchical/path/with/block/and/module ...

if (/Statement Coverage for instance (.&?) /)
{
@array = split /\//, $1;
}

for (my $eye = 1; $eye <= $#array; $eye++)
{
A miracle happens to %hash!
}

$hash{"path"}{"with"}{"block"}{"and"} now has a value of "module". Remember, the number of keys can vary. Any ideas?

It's completely unclear what you're asking. Please learn about how to create a minimal reproducible example. Also, $eye? — Matt Jacob
– Matt Jacob, Commented May 5, 2016 at 16:43

choroba · Accepted Answer · 2016-05-05 16:43:35Z

2

That's what Data::Diver does for you:

my @array = split /\//, $1;
DiveVal(\ my %hash, @array[ 0 .. $#array - 1 ]) = $array[-1];
print Dumper(\%hash);

answered May 5, 2016 at 16:43

choroba

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2 Comments

hal9e3 Over a year ago

Thanks, unfortunately that package isn't installed on my system, at least for our rev of Perl, 5.8.8, and our IT department is very reluctant to upgrade. Maybe I can try it at home on my laptop.

Sobrique Over a year ago

5.8.8 is a very old version of perl

jira · Accepted Answer · 2016-05-06 07:14:25Z

See my code below. It builds the desired hash recursively.

But I think that you are taking a wrong approach. I obviously don't know what exactly you are trying to achieve, but seems to me, that you should use tree data structure instead of the multidimensional hash.

use strict;
use warnings;

use v5.10;


use Data::Dumper;

my @data = (
  'some/path/test',
  'some/path/deeper/test',
  'another/deeper/path/test',
);

my $resultHr = {};

foreach my $path (@data) {
  my @elems = split /\//, $path;
  buildHash($resultHr, @elems);
}

say Dumper($resultHr);


sub buildValue {
  my $n = shift;

  if (@_) {
    return {$n => buildValue(@_)};
  }
  else {
    return $n;
  }
}

sub buildHash {
  my $hr = shift;
  my $k = shift;

  return unless $k;

  if (exists $hr->{$k} && ref $hr->{$k}) {
    buildHash($hr->{$k}, @_);
  }
  else {
    $hr->{$k} = buildValue(@_);
  }
}

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