Facebook open graph, filtering friends list array

Question

I want my application to filter the friends list I get using the open graph. People who login into my site must see only their friends who also use my app. I\'ve noticed this on

Answer 1

You can access the lists of a user by access the friendslist connection via graph api

example: http://developers.facebook.com/tools/explorer/?method=GET&path=me%2Ffriendlists

/me/friendlists?access_token='.$access_token.'

Answer 2

Can easily be done when you use FQL to query the user table (in conjunction with the friend table) – that has a field is_app_user, so a query like

SELECT uid, name FROM user
WHERE uid IN (SELECT uid1 FROM friend WHERE uid2 = me())
AND is_app_user

will return only those friends of the current user that are also users of your app.