php convert flat family list to tree - php

Question

this one is a little Q&A-style...
i've been searching for this situation and couldn't find any solution, so i build my own.
it took me a few days to get a working code for my needs, but now i am wondering if there's a more efficient way:
$data = [
['a','aa','aaa'],
['a','aa','aab'],
['a','aa','aac'],
['a','ab'],
['a','ac','aca'],
['b','ba'],
['b','bb'],
['b','bc'],
];
function tree($values){
$on_end = sizeof($values) == 1 && sizeof($values[0]) == 0;
if ( $on_end ) return null;
$tree1 = [];
$tree2 = [];
foreach ($values as $a){
$parent = $a[0];
//remove the first column
array_shift($a);
$tree1[ $parent ][] = $a;
}
foreach ($tree1 as $parent => $b){
$tree2[ $parent ] = tree( $b );
}
return $tree2;
}
echo "<pre>".print_r(tree($data),true)."</pre>";
this is the result:
Array
(
[a] => Array
(
[aa] => Array
(
[aaa] =>
[aab] =>
[aac] =>
)
[ab] =>
[ac] => Array
(
[aca] =>
)
)
[b] => Array
(
[ba] =>
[bb] =>
[bc] =>
)
)
if anybody got a better one, please post it!

Answer 1

You have a shortest solution ... but it's using eval function erk
<?php
$data = [
['a','aa','aaa'],
['a','aa','aab'],
['a','aa','aac'],
['a','ab'],
['a','ac','aca'],
['b','ba'],
['b','bb'],
['b','bc'],
];
function arrayToTree_eval(array $source, $defaultValue = null) {
$tree = [];
foreach( $source as $values ) {
eval(sprintf('$tree%s = $defaultValue;', '["' . implode('"]["', $values) . '"]'));
}
return $tree;
}
var_dump( arrayToTree_eval($data) );
7 lines of code, and hop !
array (size=2)
'a' =>
array (size=3)
'aa' =>
array (size=3)
'aaa' => null
'aab' => null
'aac' => null
'ab' => null
'ac' =>
array (size=1)
'aca' => null
'b' =>
array (size=3)
'ba' => null
'bb' => null
'bc' => null
:)