How to build nested array from nested object?

Question

For example, I have objects:

<?php

class A
{
    public $key;
    public $parent;
}

class B
{
    public $value;
    public $objects;
}

$a1 = new A();
$a1->key = 'a1';
$a2 = new A();
$a2->key = 'a2';
$a2->parent = $a1;
$a3 = new A();
$a3->key = 'a3';
$a3->parent = $a2;

$b = new B();
$b->objects = [$a1, $a2, $a3];
$b->value = 100;
someFunction($b);

In result I need to get array like this:

[
'a1' => ['a2' => ['a3' => 100]]
]

How can I build this array? Of Course 3 objects is just an example, this value may be bigger or smaller, so I need recursive function I think.

You want to build your object and then convert it with (array) $object? — Matt, Jul 27 '17 at 14:26
The desired effect is not sufficiently defined. Do you arrive at your result because of the parent relations or because of the value variable? Because one of these is redundant. Also you should at least try to come up with a prototype of your function and post it here. — Kempeth, Jul 28 '17 at 06:09

score 1 · Accepted Answer · answered Jul 27 '17 at 19:28

Another solution but without the global variable:

function nested($ob, $val, $res){
  if($res == array()) {
    $res = $val;
  }
  $res = array($ob->key => $res);
  if( is_object($ob->parent) ){  
    $res = nested( $ob->parent, $val, $res);
  }
  return($res);
} 

$res = nested($b->objects[count($b->objects) - 1], $b->value, array());

echo("<pre>");
print_r($b);
print_r($res);

score 0 · Answer 2 · answered Jul 27 '17 at 14:30

0

You mean associative array from object? If so You can use just:

$array = (array) $object;

Meaby this answer give You more information:

Convert PHP object to associative array

answered Jul 27 '17 at 14:30

grzesiek16016

60
6

No, I need exactly as in the example – engilexial Jul 27 '17 at 14:34

score 0 · Answer 3 · answered Jul 27 '17 at 14:34

0

The conversion from your object structure

{
  'objects':[
    {
      'key':'a1'
    },
    {
      'key':'a2',
      'parent':{
        'key':'a1'
      },
    },
    {
      'key':'a3',
      'parent':{
        'key':'a2',
        'parent':{
          'key':'a1'
        }
      }
    }
  ],
  'value':100
}

to:

[
'a1' => ['a2' => ['a3' => 100]]
]

is non-trivial. You'll have to create some kind of function for this yourself.

answered Jul 27 '17 at 14:34

Kempeth

1,856
2
22
37

yes, and I'm requesting for help for build this function =) – engilexial Jul 27 '17 at 14:36
I think that I would do this: in the last element, recursively replace, for example, `parent` with the value `key`. But can there be other options? – engilexial Jul 27 '17 at 14:38

score 0 · Answer 4 · answered Jul 27 '17 at 19:15

This was a very interesting task to solve! Thanks for posting. It is still not the perfect code because there is a global variable in the function but it works. I hope it is simple. I tested it even with four objects.

$res = array();

function nested($ob, $val){
  global $res;

  if($res == array()) {
    $res = $val; // Set the deepest value in the array to $val
  }
  // Form: put a new array around the old
  $res = array($ob->key => $res); 
  if( is_object($ob->parent) ){  
    nested( $ob->parent, $val); // parent -> go deeper
  }
} 

nested($b->objects[count($b->objects) - 1], $b->value);

echo("<pre>");
print_r($b);
print_r($res);

I hope that helped :)

How to build nested array from nested object?

4 Answers4