Thanks a lot for the quick reply, Trustmaster!

Another thing is that you might want to access items from both arrays by index, so you can use for loop instead of foreach.

Putting it all together, here is how you can add user_id property to each object in the array using values from another array:

for ($i = 0; $i < count($userid); $i++)
{
	$videos[$i]->user_id = $userid[$i];
}

I've got the following array:

Array
(
    [0] => stdClass Object
        (
            [embed_count] => 3526
            [stream_count] => 10216
            [category] => gaming
            [channel_count] => 20331
            [format] => live
            [featured] => 1
            [site_count] => 6690
            [abuse_reported] => 
            [channel] => stdClass Object
                (
                    [timezone] => America/New_York
                    [subcategory] => 
                    [category] => gaming
                    [embed_enabled] => 1
                )

            [video_height] => 720
            [language] => en
            [video_bitrate] => 2107.9375
            [id] => 4426520352
            [broadcaster] => delay
            [broadcast_part] => 3
            [audio_codec] => uncompressed
            [up_time] => Mon Dec 24 09:46:39 2012
            [video_width] => 1280
            [geo] => US
            [channel_view_count] => 18592346
            [channel_subscription] => 1
            [embed_enabled] => 1
            [stream_type] => live
            [video_codec] => AVC
        )

    [1] => stdClass Object
        (
            [embed_count] => 14
            [stream_count] => 195
            [category] => gaming
            [channel_count] => 312
            [format] => live
            [featured] => 1
            [site_count] => 181
            [abuse_reported] => 
            [channel] => stdClass Object
                (
                    [timezone] => US/Pacific
                    [subcategory] => 
                    [category] => gaming
                    [embed_enabled] => 1
                )

            [video_height] => 1080
            [language] => en
            [video_bitrate] => 4398.9375
            [id] => 4426659824
            [broadcaster] => fme
            [broadcast_part] => 2
            [audio_codec] => uncompressed
            [up_time] => Mon Dec 24 10:16:06 2012
            [video_width] => 1920
            [geo] => US
            [channel_view_count] => 5738728
            [channel_subscription] => 1
            [embed_enabled] => 1
            [stream_type] => live
            [video_codec] => AVC
        )
)

Now I want to add user_id to it and foreach loop through the array afterwards.

How can I add a new value to the existing array?
So I end up keeping the same array but with the added value, something like this:

Array
(
    [0] => stdClass Object
        (
            [user_id] => Twiebie
            [embed_count] => 3526
            [stream_count] => 10216
            etc...
            etc...
        )

    [1] => stdClass Object
        (
            [user_id] => AnotherUser
            [embed_count] => 14
            [stream_count] => 195
            etc...
            etc...
        )
)

If I do something like:

// $result is the array as seen above here
foreach ($userid as $value)
{
    $result[] = $value;
}

It adds it to the bottom of the array instead of to the stdClass Object.
This is fine too, but how would I loop through it then? With a foreach inside a foreach? Can someone provide a code example?

Thanks in advance.