Sync array values across all related array keys - php

Question

I have a PHP array with the following data
Array
(
[3] => Array
(
[0] => 4095
[2] => 651
)
[4095] => Array
(
[0] => 3
)
[651] => Array
(
[0] => 4432
)
[4432] => Array
(
[0] => 651
)
[92] => Array
(
[0] => 45
)
)
The above array has keys as student_id and the values are also student_id creating a circular relation. What I am trying to achieve is all the student_id has the same set of student_id values. Basically if student_id 3 is related to 4095, 4432 & 651, then, in turn, each of these values has to have 3 among them including other student_id from 3. The below output demonstrates what I am trying to achieve.
Array
(
[3] => Array
(
[0] => 4095
[1] => 4432
[2] => 651
)
[4095] => Array
(
[0] => 3
[1] => 4432
[2] => 651
)
[651] => Array
(
[0] => 3
[1] => 4432
[2] => 4095
)
[4432] => Array
(
[0] => 3
[1] => 4095
[2] => 651
)
[92] => Array
(
[0] => 45
)
[45] => Array
(
[0] => 92
)
)
Explanation of output
The array keys 3, 4095, 651 & 4432 are related to each other either directly or via a common relation (indirect), so will have common set of values (siblings). The key 92 in input array has a value (sibling) of 45, so in a resultant array, a new key 45 will be added to array with the inverse relation as well.
What I have tried so far
I have tried to do it with this code
$syncedSiblings = [];
foreach ($studentsWithSiblings as $sid => $siblings) {
$all = map_assoc(array_merge([$sid], array_keys($siblings)));
foreach ($all as $studentId) {
if (isset($syncedSiblings[$studentId])) {
$old = $syncedSiblings[$studentId];
$syncedSiblings[$studentId] = array_unique(array_merge($old, array_except($all, $studentId)));
} else {
$syncedSiblings[$studentId] = array_unique(array_except($all, $studentId));
}
}
}
Where $studentsWithSiblings has the above array & array_except returns array without the passed values as second argument.
This is the output I am getting right now
Array
(
[3] => Array
(
[0] => 4095
[1] => 651
)
[4095] => Array
(
[0] => 3
[1] => 651
)
[651] => Array
(
[0] => 3
[1] => 4095
[2] => 4432
)
[4432] => Array
(
[0] => 651
)
[92] => Array
(
[0] => 45
)
)
Any help with this will be highly appreciated.

Answer 1

If I've understood you correctly, then this possible to achieve with recursion:
function getChildren($ind_ar, $prev_ar, $data, $rem){
$tmp = [];
$mark = 0;
foreach($ind_ar as $ind){
foreach($data[$ind] as $new_val){
if(!in_array($new_val,$prev_ar) && $new_val != $ind && $new_val != $rem){
$mark = 1;
$tmp[] = $new_val;
}
foreach($data[$new_val] as $new){
if(!in_array($new,$prev_ar) && $new != $ind && $new != $rem){
$mark = 1;
$tmp[] = $new;
}
}
}
}
$res_ar = $prev_ar;
if(!empty($tmp)) $res_ar = array_unique(array_merge($tmp,$prev_ar));
if($mark) $res_ar = getChildren($tmp,$res_ar,$data, $rem);
return $res_ar;
}
You can use this function in this way:
$data = array( 3 => [4095, 651], 4095 => [3], 651 => [4432], 4432 => [3, 651], 92 => [45], 45 => [92], );
foreach($data as $in => &$data_val) {
$data_val = getChildren([$in],$data_val,$data, $in);
sort($data_val);
}
Demo
Output:
Array
(
[3] => Array
(
[0] => 651
[1] => 4095
[2] => 4432
)
[4095] => Array
(
[0] => 3
[1] => 651
[2] => 4432
)
[651] => Array
(
[0] => 3
[1] => 4095
[2] => 4432
)
[4432] => Array
(
[0] => 3
[1] => 651
[2] => 4095
)
[92] => Array
(
[0] => 45
)
[45] => Array
(
[0] => 92
)
)

Answer 2

Two nested loops over the data. If the keys are different, then check if the key of the inner loop is already contained in the data array of the outer key element - if not, add it.
$data = json_decode('{"3":{"0":4095,"2":651},"4095":[3],"651":[4432],"4432":{"1":651}}', true);
foreach($data as $key_outer => $val_outer) {
foreach($data as $key_inner => $val_inner) {
if($key_outer != $key_inner && !in_array($key_inner, $data[$key_outer])) {
$data[$key_outer][] = $key_inner;
}
}
}
var_dump($data);
This gets you
array (size=4)
3 =>
array (size=3)
0 => int 4095
2 => int 651
3 => int 4432
4095 =>
array (size=3)
0 => int 3
1 => int 651
2 => int 4432
651 =>
array (size=3)
0 => int 4432
1 => int 3
2 => int 4095
4432 =>
array (size=3)
1 => int 651
2 => int 3
3 => int 4095
I am assuming a specific order of the elements in those sub-items is not actually required. If it is, then please sort them yourself as desired afterwards or in between (depending on what exactly you need, f.e. sort($data[$key_outer]); after the inner loop would get you the IDs in all sub-arrays sorted ascending.)