overloading.php

<?php

class MyCollection
{
    //Iterator/ArrayAccess/Countable stuff...

    public overload -(array $other)
    {

        return new self(array_diff($this->items, $other));
    }
}


$col = new MyCollection(['a' => 1, 'b' => 2, 'c' => 3]);
$diff = $col - array_flip(['a', 'c']);

var_dump($col); // MyCollection(['b' => 2])