While some group URLs come in the format of www.facebook.com/groups/%ID%/ other come in the format of www.facebook.com/groups/%SOME_STRING%/. For example http://www.facebook.com/groups/2261122614/ vs. http://www.facebook.com/groups/fbdevelopers/.
In the former case it's very easy to programmatically extract the Graph API ID from the URL. How can that be done for URLs of the latter case?