Java / List and its implementations
Difference between removeAll() and retailAll() methods in Java collection.
removeAll drops every element also present in the argument collection. retainAll keeps only the intersection and removes everything else.
removeAll method removes the collection elements (List, Set, Vector also Collection) that exist in the specified collection of elements.
public class ArrayListEx { public static void main(String[] args) { List<String> myList = new ArrayList<>(); myList.add("A"); myList.add("B"); myList.add("C"); myList.add("D"); List<String> mySubList = myList.subList(2, 3); System.out.println("List content is " + myList); myList.removeAll(mySubList); System.out.println("List content after remove is" + myList); } }
Output: List content is [A, B, C, D] List content after remove is [A, B, D]
retainAll method retains the collection elements (List, Set, Vector also Collection) that exist in the specified collection of elements and it removes all other elements.
public class ArrayListEx { public static void main(String[] args) { List<String> myList = new ArrayList<>(); myList.add("A"); myList.add("B");myList.add("C");myList.add("D"); List<String> mySubList = myList.subList(2, 3); System.out.println("List content is " + myList); myList.retainAll(mySubList); System.out.println("List content after retaining is " + myList); } }
Output: List content is [A, B, C, D] List content after retaining is [C]
More Related questions...
