Programming Articles - Page 2895 of 3366

ArrayList is a part of the Java Collections Framework. It is used to store elements in a dynamic array that can grow as needed. Unlike arrays, ArrayLists can change their size dynamically, which makes them easier for storing collections of objects without fixing the size at the time of creation. Our task is to iterate through an ArrayList in Java. Let's look at some scenarios to understand the problem better: Scenario 1 Input : [1, 2, 3, 4, 5] Output: 1 2 3 4 5 Explanation: We will iterate through the ArrayList and print each element. Scenario 2 Input ... Read More

Let us first create a NavigableMapNavigableMap n = new TreeMap();Now, let us add some elementsn.put("A", 888); n.put("B", 999); n.put("C", 444); n.put("D", 555); n.put("E", 666); n.put("F", 888);The following is the complete example to create NavigableMap, add elements and display themExample Live Demoimport java.util.*; public class Demo { public static void main(String[] args) { NavigableMap n = new TreeMap(); n.put("A", 888); n.put("B", 999); n.put("C", 444); ... Read More

To remove the last entry of the TreeMap, use the pollLastEntry() method.Let us first create a TreeMap and add elementsTreeMap m = new TreeMap(); m.put(1, "India"); m.put(2, "US"); m.put(3, "Australia"); m.put(4, "Netherlands"); m.put(5, "Canada");Remove the last entry nowm.pollLastEntry()The following is an example to remove the last entry of the TreeMapExample Live Demoimport java.util.*; public class Demo {    public static void main(String args[]){       TreeMap m = new TreeMap();       m.put(1, "India");       m.put(2, "US");       m.put(3, "Australia");       m.put(4, "Netherlands");       m.put(5, "Canada");       System.out.println("TreeMap Elements ... Read More

The java.util.ArrayList.contains() method can be used to check if an element exists in an ArrayList or not. This method has a single parameter i.e. the element whose presence in the ArrayList is tested. Also it returns true if the element is present in the ArrayList and false if the element is not present.A program that demonstrates this is given as followsExample Live Demoimport java.util.ArrayList; import java.util.List; public class Demo {    public static void main(String[] args) {       List aList = new ArrayList();       aList.add("A");       aList.add("B");       aList.add("C");       aList.add("D"); ... Read More

The method java.util.ArrayList.removeAll() removes all the the elements from the ArrayList that are available in another collection. This method has a single parameter i.e. the Collection whose elements are to be removed from the ArrayList.A program that demonstrates this is given as followsExample Live Demoimport java.util.ArrayList; import java.util.List; public class Demo { public static void main(String args[]) throws Exception { List aList1 = new ArrayList(); aList1.add("Anna"); aList1.add("John"); aList1.add("Mary"); ... Read More

The sub-list of an ArrayList can be obtained using the java.util.ArrayList.subList() method. This method takes two parameters i.e. the start index for the sub-list(inclusive) and the end index for the sub-list(exclusive) from the required ArrayList. If the start index and the end index are the same, then an empty sub-list is returned.A program that demonstrates this is given as followsExample Live Demoimport java.util.ArrayList; import java.util.List; public class Demo { public static void main(String[] args) { ArrayList aList = new ArrayList(); aList.add("Apple"); ... Read More

Use the firstEntry() method in TreeMap to retrieve the first entry.Create a TreeMap and add some elementsTreeMap m = new TreeMap(); m.put(1, "India"); m.put(2, "US"); m.put(3, "Australia"); m.put(4, "Netherlands"); m.put(5, "Canada");Now, retrieve the first entrym.firstEntry()The following is an example to retrieve first entry in the TreeMapExample Live Demoimport java.util.*; public class Demo {    public static void main(String args[]){       TreeMap m = new TreeMap();       m.put(1, "India");       m.put(2, "US");       m.put(3, "Australia"); m.put(4, "Netherlands"); m.put(5, "Canada"); ... Read More

To get floor key means to return the greatest key less than or equal to the given key, or null if there is no such key. This can be done with the floorKey() metho.The following is an example to get floor key from NavigableMapExample Live Demoimport java.util.*; public class Demo { public static void main(String[] args) { NavigableMap n = new TreeMap(); n.put("A", 498); n.put("B", 389); n.put("C", 868); ... Read More

The navigableKeySet() method is used to get view of the Map from NavigableMap.Let us first create a NavigableMapNavigableMap n = new TreeMap();Add some elements in the NavigableMapn.put("A", 498); n.put("B", 389); n.put("C", 868); n.put("D", 988); n.put("E", 686); n.put("F", 888); n.put("G", 999); n.put("H", 444); n.put("I", 555); n.put("J", 666);Get Navigable Key Set nown.navigableKeySet()The following is an example to get navigable key setExample Live Demoimport java.util.ArrayList; import java.util.*; public class Demo { public static void main(String[] args) { NavigableMap n = new TreeMap(); n.put("A", ... Read More

An element can be retrieved from the ArrayList in Java by using the java.util.ArrayList.get() method. This method has a single parameter i.e. the index of the element that is returned.A program that demonstrates this is given as followsExample Live Demoimport java.util.ArrayList; import java.util.List; public class Demo { public static void main(String args[]) throws Exception { List aList = new ArrayList(); aList.add("James"); aList.add("George"); aList.add("Bruce"); aList.add("Susan"); ... Read More