Is it possible to sort a an array list while ignoring the first 3 characters in each string?

Question

I am trying to figure out how to sort my list alphabetically, normally this would be really easy, but I need to ignore the first 5 characters of each string in my list. (they are numerical IDS)

        ArrayList<String> tempList = new ArrayList<String>();

        for(String s : AddressBook){
        tempList.add(s);

        Collections.sort(tempList );

            }
        System.out.println(tempList);

Answer 1

You can do it by supplying your own Comparator implementation.

Collections.sort (tempList, new Comparator<String>() {
  public int compare(String o1, String o2)
  {
    String sub1 = o1.substring (3);
    String sub2 = o2.substring (3);
    return sub1.compareTo (sub2);
  }
});

Answer 2

Yes this is fairly trivial in Java 8:

Collections.sort(list, Comparator.comparing(s -> s.subString(4));

Answer 3

This answer applies for Java 8, improving performance and readability by using lambda expressions.

You might need to apply special string length checks (if your implementation provides Strings shorter than 6 characters).

Collections.sort (tempList, (o1, o2) -> o1.substring(5).compareTo(o2.substring(5)));