Question

Suppose that whe have some object, derived from these class instances

class A
{
...
 private b //list of object of class B
}

class B
{
...
 private c //list of object of class C
}

class C
{
...
 private id
}

Now, somewhere in my code, I’ve got this situation

function findId(array $idList)
{
 [...]
}

Where I have to find (for each element of $idList) if an element is contained into this object “cascade”

First solution

//object initialization
foreach($a->getB() as $b)
{
 foreach($b->getC() as $c)
 {
  foreach($idList as $id)
  {
   if($id == $c->getId())
   {
    //do something an break the cycle
   }
  }
 }
}

Second Solution

//object initialization

$idSet = array();
foreach($a->getB() as $b)
{
 foreach($b->getC() as $c)
 {
  $idSet[] = $c->getId();
 }
}
$idSet = array_unique($idSet);

foreach($idList as $id)
{
 if(array_search($id,$idSet) !== false)
 {
  [...]
 }
}

Which is better? There are some alternative methods for reach my goal?

IMPORTANT

There isn’t better data representation. This because these objects are some database object (doctrine2)

Answer 1

You can actually combine the two approaches…

foreach($a->getB() as $b)
{
 foreach($b->getC() as $c)
 {
    if (in_array($id, $idList)) {
     ...

And if you absolutely can’t optimize in a way you won’t have inner loop, set the values of $idList as keys, and values as true, and use isset() instead of in_array(), since it’s the fastest