Question: I've looking looking at this with no success so far. I need a regular expression that returns me the string after the one in a phone number. Let me give you the perfect example:

phone number (in exact format i need): 15063217711

return i need: 5063217711 --> so the FIRST char if its a 1 is removed. I need a regular expression that matches a 1 only at the BEGINNING of the string and then returns the rest of the phone number. 

By the way im using objective C but it should not make much difference.

Answer: 
For a playlist DEFINITELY the database. The preferences is just a simple key-value pair.
It all depends on the complexity of what you are going to save. SharedPreferences it's the simple approach, but I don't think it is a good idea in terms of scalability.

In your case you would be better off using SQLite just because you can create complex structures using a relational database and still being easy to develop because its well-known SQL syntax.