Codecombat is a platform very similar to Swift playground with the advantage of being cross-platform and usable by any browser. If you are going to learn to program python and javascript without getting bored codecombat could be for you.
All you have to do is control your avatar by issuing commands in python or javascript. It starts from rather simple levels and gradually the complexity increases.
There are various types of accounts, some for a fee, but you can try the free version without any problem, registration is not required. www.codecombat.com
Good fun!