objective-c get last 2 characters of a string?

问题

Say I have a string:

NSString *state = @"California, CA";

Can someone please tell me how to extract the last two characters from this string (@"CA" in this example)

回答1:

NSString *code = [state substringFromIndex: [state length] - 2];

should do it

回答2:

Swift 4:

let code = (state as? NSString)?.substring(from: state.characters.count - 2)

来源：https://stackoverflow.com/questions/3483223/objective-c-get-last-2-characters-of-a-string