Flat array to a hierarchical multi-dimensional array - php

Question

I have an flat array that looks like this exemple :
array (
0 =>
array (
'TreePad_Fields' =>
array (
'#ID' => '1',
'#NAME' => '[CDATA[nomenclature exemple]]',
'#LEVEL' => '0',
),
),
1 =>
array (
'TreePad_Fields' =>
array (
'#ID' => '3',
'#NAME' => '[CDATA[droit]]',
'#LEVEL' => '1',
),
),
2 =>
array (
'TreePad_Fields' =>
array (
'#ID' => '13',
'#NAME' => '[CDATA[législation]]',
'#LEVEL' => '2',
),
),
3 =>
array (
'TreePad_Fields' =>
array (
'#ID' => '14',
'#NAME' => '[CDATA[statuts]]',
'#LEVEL' => '3',
),
),
4 =>
array (
'TreePad_Fields' =>
array (
'#ID' => '15',
'#NAME' => '[CDATA[projets de loi]]',
'#LEVEL' => '4',
),
),
5 =>
array (
'TreePad_Fields' =>
array (
'#ID' => '16',
'#NAME' => '[CDATA[réglementations]]',
'#LEVEL' => '2',
),
),
6 =>
array (
'TreePad_Fields' =>
array (
'#ID' => '17',
'#NAME' => '[CDATA[instruments statutaires]]',
'#LEVEL' => '3',
),
),
7 =>
array (
'TreePad_Fields' =>
array (
'#ID' => '2',
'#NAME' => '[CDATA[économie]]',
'#LEVEL' => '1',
),
),
8 =>
array (
'TreePad_Fields' =>
array (
'#ID' => '8',
'#NAME' => '[CDATA[analyse cout-avantage]]',
'#LEVEL' => '2',
),
),
9 =>
array (
'TreePad_Fields' =>
array (
'#ID' => '6',
'#NAME' => '[CDATA[analyse socio-économique]]',
'#LEVEL' => '2',
),
),
)
and I would like to have like this :
$data = array(
'[CDATA[nomenclature exemple]]' => array(
'[CDATA[droit]]' => array(
'[CDATA[législation]]' => array(
'[CDATA[statuts]]' => array(
'[CDATA[projets de loi]]'
),
),
'[CDATA[réglementations]]' => array(
'[CDATA[instruments statutaires]]'
),
),
'[CDATA[économie]]' => array(
'[CDATA[analyse cout-avantage]]',
'[CDATA[analyse socio-économique]]',
),
)
);
I can't figure out how to do it. I've found other examples here for converting flattened arrays into multidimensional ones but not where there's a custom child like this.

Answer 1

I should say it is a bit inconsistent to want to have the leaves in the datastructure have the [CDATA...] name as value of an indexed array, while in the rest of the tree they are keys.
So, I would suggest to make those leaves also keyed by the [CDATA...] name, but just with an empty array as value. That way the structure is consistent throughout.
For that structure you could use this function:
function buildTree($data) {
foreach($data as $i => $row) {
$arr = $row['TreePad_Fields'];
$level = $arr['#LEVEL'];
$key = $arr['#NAME'];
$levels[$level][$key] = [];
$levels[$level+1] = &$levels[$level][$key];
}
return $levels[0];
}
Call it like this:
$result = buildTree($data);
For the sample data given, the result would be:
array (
'[CDATA[nomenclature exemple]]' => array (
'[CDATA[droit]]' => array (
'[CDATA[législation]]' => array (
'[CDATA[statuts]]' => array (
'[CDATA[projets de loi]]' => array (),
),
),
'[CDATA[réglementations]]' => array (
'[CDATA[instruments statutaires]]' => array (),
),
),
'[CDATA[économie]]' => array (
'[CDATA[analyse cout-avantage]]' => array (),
'[CDATA[analyse socio-économique]]' => array (),
),
),
)
See it run on eval.in