PHP assoc array to class instance

Question

I saw that the conversion from a class instance (object) to associative array is a simple cast :

$array =  (array) $yourObject;

So if i have class A and an associative array contaning the neccesary fields to fill a class A object would it be enough to do the opposite? eg

$aInstance=(A)$assocArray;

If not whats the easiest way to do so?

Answer 1

Things are not that easy, since there is no way for php to somehow magically guess what to do with the values of that array. Objects are a structured set of data unlike an array. So you need a description of the structure and rules how to use it.

You need to implement a constructor in the class definition, then you can construct a new object based on some given array. Take a look at this arbitrary example:

<?php
class A {
    protected $title;
    protected $data;
    public function __construct ($data) {
        $this->title = $data['title'];
        $this->data = sprintf('this is foo: %s', $data['foo']);
    }
    public function __toString() {
        return sprintf(
            "I am an object titled '%s'\nI hold that foo value: %s\n",
            $this->title,
            $this->data
        );
    }
}

$data = [
    'title' => 'hello world',
    'foo' => 'foovalue',
    'bar' => 'barvalue'
];
$object = new A($data);
echo $object;
var_dump($object);

The obvious output is:

I am an object titled 'hello world'
I hold that foo value: this is foo: foovalue
/home/arkascha/test.php:25:
class A#1 (2) {
  protected $title =>
  string(11) "hello world"
  protected $data =>
  string(21) "this is foo: foovalue"
}