Symfony 3 - difference between 2 arraycollection - diff

Question

Is there a way to differentiate 2 ArrayCollection ? (like array_diff)
today I loop on the first and check if $it->contains() match, but I think it can be refactored.

Answer 1

You can use array_diff in the following way:
$diff = array_diff($arrayCollection1->toArray(), $arrayCollection2->toArray());
$arrayCollectionDiff = new ArrayCollection($diff);

Answer 2

I would suggest the following:
A class made of two functions:
function getElementFromANotInB gives the elements from ArrayCollection A not in ArrayCollection B (can also be used the other way around to get elements from B not in A);
function getElementCommonInAAndB gives common elements of ArrayCollection A and B.
Here is the class:
<?php
namespace [Bundle name]\DependencyInjection\ToolBox\ArrayCollectionTB;
use Doctrine\Common\Collections\ArrayCollection;
class ArrayCollectionTB {
public function __construct(){}
public function getElementFromANotInB(ArrayCollection $acA,ArrayCollection $acB){
return $elementsInANotInB = $acA->filter(function($a) use ($acB) {
return $acB->contains($a)===false;
});
}
public function getElementCommonInAAndB(ArrayCollection $acA,ArrayCollection $acB){
return $elementsCommonInAAndB = $acA->filter(function($a) use ($acB) {
return $acB->contains($a)===true;
});
}
}
?>
Here is the test class that comes with it:
<?php
namespace Tests\[Bundle name]\DependencyInjection\ToolBox\ArrayCollectionTB;
use [Bundle name]\DependencyInjection\ToolBox\ArrayCollectionTB\ArrayCollectionTB;
use Doctrine\Common\Collections\ArrayCollection;
use PHPUnit\Framework\TestCase;
use Symfony\Bundle\FrameworkBundle\Test\KernelTestCase;
/**
* #coversDefaultClass [Bundle name]\DependencyInjection\ToolBox\ArrayCollectionTB
*/
class ArrayCollectionTBTest extends KernelTestCase{
private static $acA;
private static $acB;
private static $acTB;
public static function setUpBeforeClass()
{
//start the symfony kernel
$kernel = static::createKernel();
$kernel->boot();
//get the DI container
$container = $kernel->getContainer();
self::$acA = new ArrayCollection();
self::$acB = new ArrayCollection();
//acA and acB have in common 1,5
//acA has 2 and 3 not in acB
self::$acA->add('element 1');
self::$acA->add('element 2');
self::$acA->add('element 3');
self::$acA->add('element 5');
//acB has 4 and 6 not in acA
self::$acB->add('element 1');
self::$acB->add('element 4');
self::$acB->add('element 5');
self::$acB->add('element 6');
self::$acTB = new ArrayCollectionTB();
}
/**
* #covers ::getElementFromANotInB
* #testdox test check dif give element from ArrayCollection A not in ArrayCollection B
*/
public function testGetElementFromANotInB(){
$res = self::$acTB->getElementFromANotInB(self::$acA,self::$acB);
//result should be 2 and 3
$this->assertNotContains('element 1',$res);
$this->assertContains('element 2',$res);
$this->assertContains('element 3',$res);
$this->assertNotContains('element 4',$res);
$this->assertNotContains('element 5',$res);
$this->assertNotContains('element 6',$res);
}
/**
* #covers ::getElementFromANotInB
* #testdox test check dif give element from ArrayCollection B not in ArrayCollection A
*/
public function testGetElementFromBNotInA(){
$res = self::$acTB->getElementFromANotInB(self::$acB,self::$acA);
$this->assertNotContains('element 1',$res);
$this->assertNotContains('element 2',$res);
$this->assertNotContains('element 3',$res);
$this->assertContains('element 4',$res);
$this->assertNotContains('element 5',$res);
$this->assertContains('element 6',$res);
}
/**
* #covers ::getElementCommonInAAndB
* #testdox test check gives element from ArrayCollection A and ArrayCollection A
*/
public function testGetElementFromBAndA(){
$res = self::$acTB->getElementCommonInAAndB(self::$acB,self::$acA);
$this->assertContains('element 1',$res);
$this->assertNotContains('element 2',$res);
$this->assertNotContains('element 3',$res);
$this->assertNotContains('element 4',$res);
$this->assertContains('element 5',$res);
$this->assertNotContains('element 6',$res);
}
}
?>

Answer 3

When ArrayCollection is an array of objects:
$collFoo = ArrayCollection($arrayOfFooObjects);
$collBar = ArrayCollection($arrayOfBarObjects);
$diff = $collFoo->filter(function (Foo $fooObject) use ($collBar) {
return !$collBar->contains($fooObject);
});
Simple array_diff throws an error: Error: Object of class Foo could not be converted to string