PHP : Remove object from array

Question

What is an elegant way to remove an object from an array of objects in PHP ?

Just to be clear ..

class Data{    private $arrObservers;    public add(Observer $o) {       array_push($this->arrObservers, $o);     }       public remove(Observer $o) {       // I NEED THIS CODE to remove $o from $this->arrObservers   }    } 

Answer 1

You can do

function unsetValue(array $array, $value, $strict = TRUE) {     if(($key = array_search($value, $array, $strict)) !== FALSE) {         unset($array[$key]);     }     return $array; } 

You can also use spl_object_hash to create a hash for the objects and use that as array key.

However, PHP also has a native Data Structure for Object collections with SplObjectStorage:

$a = new StdClass; $a->id = 1; $b = new StdClass; $b->id = 2; $c = new StdClass; $c->id = 3;  $storage = new SplObjectStorage; $storage->attach($a); $storage->attach($b); $storage->attach($c); echo $storage->count(); // 3  // trying to attach same object again $storage->attach($c); echo $storage->count(); // still 3  var_dump( $storage->contains($b) ); // TRUE $storage->detach($b); var_dump( $storage->contains($b) ); // FALSE 

SplObjectStorage is Traversable, so you can foreach over it as well.

On a sidenote, PHP also has native interfaces for Subject and Observer.

Answer 2

I agree with the answers above, but for the sake of completeness (where you may not have unique IDs to use as a key) my preferred methods of removing values from an array are as follows:

/**  * Remove each instance of a value within an array  * @param array $array  * @param mixed $value  * @return array  */ function array_remove(&$array, $value) {     return array_filter($array, function($a) use($value) {         return $a !== $value;     }); }  /**  * Remove each instance of an object within an array (matched on a given property, $prop)  * @param array $array  * @param mixed $value  * @param string $prop  * @return array  */ function array_remove_object(&$array, $value, $prop) {     return array_filter($array, function($a) use($value, $prop) {         return $a->$prop !== $value;     }); } 

Which are used in the following way:

$values = array(     1, 2, 5, 3, 5, 6, 7, 1, 2, 4, 5, 6, 6, 8, 8, ); print_r(array_remove($values, 6));  class Obj {     public $id;     public function __construct($id) {         $this->id = $id;     } } $objects = array(     new Obj(1), new Obj(2), new Obj(4), new Obj(3), new Obj(6), new Obj(4), new Obj(3), new Obj(1), new Obj(5), ); print_r(array_remove_object($objects, 1, 'id')); 

Hope that helps.