Introduction to Programming

Removing elements

Two methods allow the direct removal of Map elements:

• V remove(Object key): It removes an object associated with the key and returns its value, or, if such a key is not present in the map, returns null
• boolean remove(Object key, Object value): It removes an object associated with the key only if the current value associated with the key equals the provided one; returns true, if the element was removed

Here is the code that illustrates the described behavior:

Map<Integer, String> map = new HashMap<>();map.put(1, null);map.put(2, "s2");map.put(3, "s3");System.out.println(map.remove(2));        //prints: s2System.out.println(map);                  //prints: {1=null, 3=s3}System.out.println(map.remove(4));        //prints: nullSystem.out.println(map);  ...