How do I sort an ArrayList lexicographically?

Question

I am trying to sort an ArrayList of Strings that represent card values. So, some cards contain letters ("King") and some contain Strings containing only a number ("7"). I know to use Collections.sort, but it only sorts Strings that contain letters. How do I get the ArrayList to be sorted by number as well as alphabetically?

Edit: Sorry, I must not have been paying much attention when I looked at the sorting. The sort works correctly, I must have just been thrown off by the fact that a 10 will come before a 2. Thanks

Answer 1

No, Collections.sort will sort everything, using an Unicode ordinal lexicographic comparison as that's the behaviour of String.compareTo. "7" will come before "King", and "10" will come before "2".

Answer 2

As I understand, you have an array like ["7", "Queen", "9", "6"] and you want it to look like ["Queen", "9", "7", "6"] (or in reverse order) after sorting is done.

I'd recommend to make it a bit more object-oriented i.e. create class Card with fields name and value:

class Card {
   private final String name;
   private final int value;
   ...
   //constructor and getters
}

and after that create instances in this manner:

Card six = new Card("6", 6);
Card ten = new Card("10", 10);
Card queen = new Card("Queen", 12);

After that it'll be much easier to make all operations with cards (and sorting particularly) using field value instead of cards' names.