Hey again everyone! My Japanese has been lapsing lately (again) and I thought it was about time I did a bit of studying. Atm I'm just going through the grammar for JLPT 4 and I came across this example sentence:

私は学生で友だちはいしゃです

I'm completely stumped! What's this で all about? Whose friend is a doctor? :S

If anyone could translate the sentence and then explain what that で is there for, that'd be great. Thanks!