uniq.php

<?php

class MyClass {
    public $id;
    public $attribute;
    public $value;

    function __construct($i, $a, $v)
    {
        $this->id = $i;
        $this->attribute = $a;
        $this->value= $v;
    }

    function __toString()
    {
        $superRareString = '#~F50mgtlhOy~#';
        return $this->attribute . $superRareString . $this->value;
    }
}

$list = [new MyClass(1,1,2), new MyClass(2,1,5), new MyClass(3,1,8)];



function unique($array)
{
    return array_unique( $array );
}

print_r( unique($list) );