ArrayList 정렬 및 자르기

1. ArrayList 정렬

Collections sort(students, new Comparator<Student>() {
                     public int compare(Student s1,Student s2) {
                           if(s1.getName() != null && s2.getName() != null && s1.getName().comareTo(s1.getName()) != 0) {
                               return s1.getName().compareTo(s2.getName());
                           }
                          else {
                             return s1.getAge().compareTo(s2.getAge());
                          }
                      }
);

 

2. ArrayList 자르기

List<Integer> numbers = new ArrayList<Integer>(
        Arrays.asList(5,3,1,2,9,5,0,7)
 );
List<Integer> head = numbers.subList(0, 4);
List<Integer> tail = numbers.subList(4, 8);
System.out.println(head); // prints "[5, 3, 1, 2]"
System.out.println(tail); // prints "[9, 5, 0, 7]"
Collections.sort(head);
System.out.println(numbers); // prints "[1, 2, 3, 5, 9, 5, 0, 7]"
tail.add(-1);
System.out.println(numbers); // prints "[1, 2, 3, 5, 9, 5, 0, 7, -1]"