How to clone an array of objects in PHP?

Question

I have an array of objects. I know that objects get assigned by \"reference\" and arrays by \"value\". But when I assign the array, each element of the array is referencing

Answer 1

You need to loop it (possibly using a function like array_map() for that), there is no PHP function to automatically perform a deep copy of an array.

Answer 2

Just include this function in all of your classes. This will do a deep clone of all objects in case if you have arrays of objects within the object itself. It will trigger all of the __clone() functions in these classes:

/**
 * Clone the object and its properties
 */
public function __clone()
{
    foreach ($this as $key => $property)
    {
        if(is_array($property))
        {
            foreach ($property as $i => $o)
            {
                if(is_object($o)) $this->$key[$i] = clone $o;
                else $this->$key[$i] = $o;
            }
        }
        else if(is_object($property)) $this->$key = clone $property;
        else $this->$key = $property;
    }
}

Answer 3

I opted for clone as well. Cloning an array does not work (you could consider some arrayaccess implementation to do so for you), so as for the array clone with array_map:

class foo {
    public $store;
    public function __construct($store) {$this->store=$store;}
}

$f = new foo('moo');
$a = array($f);

$b = array_map(function($o) {return clone $o;}, $a);

$b[0]->store='bar';    
var_dump($a, $b);

Array clone with serialize and unserialize

If your objects support serialisation, you can even sort of deep shallow copy/clone with a tour into their sleeping state and back:

$f = new foo('moo');
$a = array($f);

$b = unserialize(serialize($a));

$b[0]->store='bar';
var_dump($a, $b);

However, that can be a bit adventurous.