PHP: Link address of multiple array keys into another bigger array - php

Question

I want to combine 3 small arrays that have unique keys between them into 1 big array but when I modify a value in the big array I want it also to reflect in the corresponding small array.
For example I have these 3 small arrays:
$arr1 = ['key1' => 'data1', 'key2' => 'data2'];
$arr2 = ['key3' => 'data3', 'key4' => 'data4', 'key5' => 'data5'];
$arr3 = ['key6' => 'data6'];
I want to have a $bigArray that has each key's address linked/mapped to each value of the small arrays. So if I do something like:
$bigArray['key4'] = 'something else';
then it would modify $arr2['key4'] to the same value ('something else').
If I try something like:
$bigArray = [&$arr1, &$arr2, &$arr3];
It has the unfortunate effect of making a multidimensional array with the keys to the values mapped.

Answer 1

Two ways i found
<?php
error_reporting(E_ALL);
$arr1 = ['key1' => 'data1', 'key2' => 'data2'];
$arr2 = ['key3' => 'data3', 'key4' => 'data4', 'key5' => 'data5'];
$arr3 = ['key6' => 'data6'];
$big = [];
if (true) {
foreach (['arr1', 'arr2', 'arr3'] as $v) {
foreach (array_keys($$v) as $k) {
$big[$k] = &${$v}[$k];
}
}
}
else {
foreach ([&$arr1, &$arr2, &$arr3] as &$v) {
foreach (array_keys($v) as $k) {
$big[$k] = &$v[$k];
}
}
}
$big['key1'] = 'data1mod';
print_r($big);
print_r($arr1);
3rd way with function
$big = [];
$bindToBig = function (&$a) use (&$big) {
foreach (array_keys($a) as $k) {
$big[$k] = &$a[$k];
}
};
$bindToBig($arr1);
$bindToBig($arr2);
$bindToBig($arr3);

Answer 2

You can't bind data that way, but you can link them in the same object:
class ArrayLink {
public $bigArray;
public $linkedChildrenArray;
protected $childrenArray;
public function __construct( $childrenArray ) {
$this->childrenArray = $childrenArray;
}
public function changeValueForKey( $arrKey, $arrValue ) {
foreach ( $this->childrenArray as $key => $value ) {
foreach ( $value as $subKey => $subValue ) {
if ( $arrKey == $subKey ) {
$this->bigArray[ $subKey ] = $arrValue;
$this->childrenArray[ $key ][ $subKey ] = $arrValue;
}
}
}
$this->linkedChildrenArray = (object) $this->childrenArray;
}
}
As you can see, the $arr2 now need to be access from $arrayLink object:
$arr1 = [ 'key1' => 'data1', 'key2' => 'data2' ];
$arr2 = [ 'key3' => 'data3', 'key4' => 'data4', 'key5' => 'data5' ];
$arr3 = [ 'key6' => 'data6' ];
$arrayLink = new ArrayLink( array( 'arr1' => $arr1, 'arr2' => $arr2, 'arr3' => $arr3 ) );
$arrayLink->changeValueForKey( 'key3', 'new value for key 3' );
echo $arrayLink->bigArray['key3']; //new value for key 3
echo $arrayLink->linkedChildrenArray->arr2['key3']; //new value for key 3