finding value of next element in an array

[eluser]vtatds[/eluser]
sorry. i think i didn't appropriately state the question. the array is an associative array.

Code:

array(4)
{
    [0]=>  object(stdClass)#18 (10)
    {
        ["activity_name"]=>  string(4) "Bowling"
        ["notes"]=>  string(20) "these are some notes"
    }
    [1]=>  object(stdClass)#19 (10)
    {
        ["activity_name"]=>  string(4) "Bowling"
        ["notes"]=>  NULL
    }
    [2]=>  object(stdClass)#20 (10)
    {
        ["activity_name"]=>  string(4) "Golf"
        ["notes"]=>  NULL
    }
    [3]=>  object(stdClass)#21 (10)
    {
        ["activity_name"]=>  string(5) "Tennis"
        ["notes"]=>  NULL
    }      
}

i'm trying to find out if array(1) has the same value for activity_name as array(0) when i'm on array(0) and so on till the end of the array