John Davidson

Message:

I have two arrays that contain objects:

array $a (size=2)

    0 => 

       object(A)

       private '_id' => int 10

    1 => 

       object(A)

       private '_id' => int 11



array $b (size=1)

    0 => 

       object(B)

       private '_id' => int 10

I'm trying to find which item in array $a doesn't exist in array $b, which in this case is $a[1]. Looping both arrays can do this, but I would like a more effective way.

---

My Answer:
One way to achieve this is by using array_udiff() function in PHP. This function compares two arrays and returns the values from the first array that are not present in the second array based on a user-defined comparison function.

Here's an example of how you can use array_udiff() to find the items in array $a that don't exist in array $b:

php
function compareObjects($a, $b) {
return $a->_id - $b->_id;
}

$diff = array_udiff($a, $b, 'compareObjects');

print_r($diff);


In this example, the compareObjects() function compares the objects based on their '_id' property. The array_udiff() function then returns the objects from array $a that are not present in array $b based on this comparison function.

After running this code, the $diff array will contain the object from array $a that doesn't exist in array $b.