Wordpress - 访问Array中的Wp对象并检索所有ID

Question

I've created a query getting only some users with specific criteria. I store these users into an array. My problem is to get back from this array only specific values like ids.

I print_r my function myfriends() and I get something like this:

Array ( 
[0] => Array ( 
    [0] => Array ( 
        [0] => WP_User Object ( 
            [data] => stdClass Object ( 
                [ID] => 48 
                ) 
            ) 
        [1] => WP_User Object ( 
            [data] => stdClass Object ( 
                [ID] => 47 
                ) 
            ) 
    ) 
[1] => 
) 

)

I need to retrieve all the ids of users in array so I've tried with:

$myfriends = myfriends($user_id); //good

$myfriendsids = $myfriends->ID; //not working
$myfriendsids = $myfriends[0]->ID; //not working
$myfriendsids = $myfriends[0][0]->ID; //not working
$myfriendsids = $myfriends[0][0][0]->ID; //only the first user id!

//even tried
$myuserdata = $myfriends->data; //not working
$myuserids = $myuserdata->ID; //not working

How can I get all the user ids I have? NB. "not working" means that I print_r all the variables and I get nothing. Thanks!

Answer 1

Tweaking a bit I've accessed and stored ids values with a foreach loop in $myfriendsids. Cool.