Programming Articles - Page 2893 of 3363

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

Elements can be filled in a Java char array in a specified range using the java.util.Arrays.fill() method. This method assigns the required char value in the specified range to the char array in Java.The parameters required for the Arrays.fill() method are the array name, the index of the first element to be filled(inclusive), the index of the last element to be filled(exclusive) and the value that is to be stored in the array elements.A program that demonstrates this is given as followsExample Live Demoimport java.util.Arrays; public class Demo { public static void main(String[] argv) throws Exception { ... Read More

Returning a shallow copy means to copy elements of one IdentityHashMap to another. For this, clone() method is used.The following is an example to return a shallow copy of IdentityHashMapExample Live Demoimport java.util.*; public class Demo { public static void main(String[] args) { IdentityHashMap m = newIdentityHashMap(); m.put("1", 100); m.put("2", 200); m.put("3", 300); m.put("4", 150); m.put("5", 110); m.put("6", 50); m.put("7", 90); m.put("8", 250); m.put("9", 350); m.put("10", 450); System.out.println("IdentityHashMap elements"+ m); System.out.println("Size = " + m.size()); System.out.println("Cloned Map = " + m.clone()); 0System.out.println("Size = " + m.size()); } }OutputIdentityHashMap elements {2=200, 4=150, 9=350, 7=90, 10=450, 6=50, 5=110, 8=250, 1=100, 3=300} Size = 10 Cloned Map = {2=200, 4=150, 9=350, 7=90, 10=450, 6=50, 5=110, 8=250, 1=100, 3=300} Size = 10

Use the containsValue() method to check whether a particular value exists in IdentityHashMap or not.Create a IdentityHashMapMap m = newIdentityHashMap(); m.put("1", 100); m.put("2", 200); m.put("3", 300); m.put("4", 150); m.put("5", 110); m.put("6", 50); m.put("7", 90); m.put("8", 250); m.put("9", 350); m.put("10", 450);Now, let’s say we need to check whether value 100 exists or not. For that, use the containsValue() method like thism.containsValue(100)The following is an example to check for the existence of a value in IdentityHashMapExample Live Demoimport java.util.*; public class Demo { public static void main(String[] args) { Map m = newIdentityHashMap(); ... Read More

Use the containsKey() method to check whether a particular key exists in IdentityHashMap or not.Create a IdentityHashMapMap m = newIdentityHashMap(); m.put("1", 100); m.put("2", 200); m.put("3", 300); m.put("4", 150); m.put("5", 110); m.put("6", 50); m.put("7", 90); m.put("8", 250); m.put("9", 350); m.put("10", 450);Now, let’s say we need to check whether key 7 exists or not. For that, use the containsKey() method like thism.containsKey(“7”)The following is an example to check for the existence of a key in IdentityHashMapExample Live Demoimport java.util.*; public class Demo {    public static void main(String[] args) {       Map m = newIdentityHashMap();       m.put("1", 100);   ... Read More

Use the clear() method to remove all the elements from IdentityHashMap in Java.Create a IdentityHashMap and add some elementsMap m = newIdentityHashMap(); m.put("1", 100); m.put("2", 200); m.put("3", 300); m.put("4", 150); m.put("5", 110); m.put("6", 50); m.put("7", 90); m.put("8", 250); m.put("9", 350); m.put("10", 450);Now, let us remove all the elementm.clear();The following is an example to remove all elements in IdentityHashMap in JavaExample Live Demoimport java.util.*; public class Demo {    public static void main(String[] args) {       Map m = newIdentityHashMap();       m.put("1", 100);       m.put("2", 200);       m.put("3", 300);       m.put("4", 150); ... Read More

To get the first value in TreeSet, use the first() method.First, get the TreeSet and add elements to itTreeSet tSet = new TreeSet(); tSet.add("10"); tSet.add("20"); tSet.add("30"); tSet.add("40"); tSet.add("50"); tSet.add("60");Now, get the first valuetSet.first()The following is an example to get the first value in TreeSetExample Live Demoimport java.util.*; public class Demo {    public static void main(String args[]){       TreeSet tSet = new TreeSet();       tSet.add("10");       tSet.add("20");       tSet.add("30");       tSet.add("40");       tSet.add("50");       tSet.add("60");       System.out.println("TreeSet elements...");       Iterator i = tSet.iterator(); ... Read More

To get Head Set, you need to use the headset() method. This allow a user to get a set of elements in sorted order.Firstly, set the TreeSet and add elementsTreeSet tSet = new TreeSet(); tSet.add("P"); tSet.add("Q"); tSet.add("R"); tSet.add("S");Let us now get the Head SetSortedSet s = tSet.headSet("S");The following is an example to get Head Set from TreeSet in JavaExample Live Demoimport java.util.*; public class Demo {    public static void main(String args[]){       TreeSet tSet = new TreeSet();       tSet.add("P");       tSet.add("Q");       tSet.add("R");       tSet.add("S");       System.out.println("TreeSet elements..."); ... Read More

Create TreeSet and add elements to itTreeSet tSet = new TreeSet(); tSet.add("P"); tSet.add("Q"); tSet.add("R"); tSet.add("S");Now, let us traverse elements in descending orderIterator j = tSet.descendingIterator(); while(j.hasNext()) {    System.out.println(j.next()); }The following is an example to traverse TreeSet elements in descending orderExample Live Demoimport java.util.*; public class Demo {    public static void main(String args[]){       TreeSet tSet = new TreeSet();       tSet.add("P");       tSet.add("Q");       tSet.add("R");       tSet.add("S");       System.out.println("TreeSet elements...");       Iterator i = tSet.iterator();       while(i.hasNext()){          System.out.println(i.next());     ... Read More

To get the size of IdentityHashMap, use the size() method. It returns the count of elements in the IdentityHashMap.Let us first create a IdentityHashMap and add some elements to itMap m = new IdentityHashMap(); m.put("1", 100); m.put("2", 200); m.put("3", 300); m.put("4", 150); m.put("5", 110); m.put("6", 50); m.put("7", 90); m.put("8", 250); m.put("9", 350); m.put("10", 450);Now, get the sizem.size();The following is an example to get the size of the IdentityHashMapExample Live Demoimport java.util.*; public class Demo { public static void main(String[] args) { Map m = newIdentityHashMap(); m.put("1", ... Read More