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Java Articles
Page 33 of 450
Copy all elements of ArrayList to an Object Array in Java
All the elements of an ArrayList can be copied into an Object Array using the method java.util.ArrayList.toArray(). This method does not have any parameters and it returns an Object Array that contains all the elements of the ArrayList copied in the correct order.A program that demonstrates this is given as follows −Exampleimport java.util.ArrayList; import java.util.List; public class Demo { public static void main(String[] args) { List aList = new ArrayList(); aList.add("Nathan"); aList.add("John"); aList.add("Susan"); aList.add("Betty"); aList.add("Peter"); Object[] objArr = ...
Read MoreIterate over the elements of HashSet in Java
Declare a HashSet and add elements −Set hs = new HashSet(); hs.add(20); hs.add(39); hs.add(67); hs.add(79);Now, iterate over the elements −for (Iterator i = hs.iterator(); i.hasNext();) { Object ele = i.next(); System.out.println(ele); }The following is an example that iterate over the elements of HashSet −Exampleimport java.util.HashSet; import java.util.Iterator; import java.util.Set; public class Demo { public static void main(String[] argv) throws Exception { Set hs = new HashSet(); hs.add(20); hs.add(39); hs.add(67); hs.add(79); System.out.println("Elements = "); for (Iterator i ...
Read MoreConvert array to HashSet in Java
Create an array and convert it to List −Integer[] arr = { 10, 15, 20, 10, 10, 10, 20, 30, 35, 40, 40}; List l = Arrays.asList(arr);Now, let us convert the above array to HashSet −Set s = new HashSet(l);The following is an example to convert array to HashSet −Exampleimport java.util.*; public class Demo { public static void main(String[] argv) throws Exception { Integer[] arr = { 10, 15, 20, 10, 10, 10, 20, 30, 35, 40, 40}; List l = Arrays.asList(arr); Set s = new HashSet(l); for (Iterator i = s.iterator(); i.hasNext();) { Object ele = i.next(); System.out.println(ele); } } }Output35 20 40 10 30 15
Read MoreNavigableMap clear() Method in Java
Clear the NavigableMap in Java, using the clear() method.Let us first create a NavigableMap and add some elements to it −NavigableMap n = new TreeMap(); n.put(5, "Tom"); n.put(9, "John"); n.put(14, "Jamie"); n.put(1, "Tim"); n.put(4, "Jackie"); n.put(15, "Kurt"); n.put(19, "Tiger"); n.put(24, "Jacob");Now, use the clear() method −n.clear();The following is an example to implement clear() method and clear the NavigableMap −Exampleimport java.util.*; public class Demo { public static void main(String[] args) { NavigableMap n = new TreeMap(); n.put(5, "Tom"); n.put(9, "John"); n.put(14, "Jamie"); n.put(1, "Tim"); ...
Read MoreInitialize a Set without using add() method in Java
With Java, you can initialize a set without using add() method.For this create a string array −String arr[] = { "A", "B", "C", "D", "E"};Now, use Set and asList() method to initialize the above string array to our Set −Set s = new HashSet(Arrays.asList(arr));The following is an example to initialize a set without using add() method −Exampleimport java.util.Arrays; import java.util.HashSet; import java.util.Set; public class Demo { public static void main(String[] a) { String arr[] = { "A", "B", "C", "D", "E"}; Set s = new ...
Read MoreNavigableSet Class floor() method in Java
The floor() method returns the greatest element less than or equal to the given element i.e. 30 here −floor(30)The following is an example to implement the floor method in Java −Exampleimport java.util.NavigableSet; import java.util.TreeSet; public class Demo { public static void main(String[] args) { NavigableSet set = new TreeSet(); set.add(10); set.add(25); set.add(40); set.add(55); set.add(70); set.add(85); set.add(100); System.out.println("Returned Value = " + set.floor(30)); } }OutputReturned Value = 25
Read MoreNavigableSet Class higher() method in Java
The higher() method in NavigableSet returns the least element strictly greater than the given element i.e. 35 here −higher(35);The following is an example to implement the higher method in Java −Exampleimport java.util.NavigableSet; import java.util.TreeSet; public class Demo { public static void main(String[] args) { NavigableSet set = new TreeSet(); set.add(10); set.add(25); set.add(40); set.add(55); set.add(70); set.add(85); set.add(100); System.out.println("Returned Value = " + set.higher(35)); } }OutputReturned Value = 40
Read MoreRemove specified element from Java LinkedHashSet
To remove a specified element from LinkedHashSet, use the remove() and include the element you want to remove as a parameter.First, set LinkedHashSet and add elements −LinkedHashSet hashSet = new LinkedHashSet(); hashSet.add(10); hashSet.add(20); hashSet.add(30); hashSet.add(40); hashSet.add(50); hashSet.add(60);Let us now remove an element −hashSet.remove(10);The following is an example to remove specified element from LinkedHashSet −Exampleimport java.util.LinkedHashSet; public class Demo { public static void main(String[] args) { LinkedHashSet hashSet = new LinkedHashSet(); hashSet.add(10); hashSet.add(20); hashSet.add(30); ...
Read MoreCreate NavigableMap from TreeMap in Java
To create NavigableMap from TreeMap. The following is the declaration −NavigableMap n = new TreeMap();Now, add some elements to the NavigableMap created above −n.put("A", 888); n.put("B", 999); n.put("C", 444); n.put("D", 555); n.put("E", 666); n.put("F", 888); n.put("G", 999); n.put("H", 444); n.put("I", 555); n.put("J", 666);The following is an example to create NavigableMap from TreeMap and display it −Exampleimport java.util.*; public class Demo { public static void main(String[] args) { NavigableMap n = new TreeMap(); n.put("A", 888); n.put("B", 999); ...
Read MoreRemove all elements from Java LinkedHashSet
To remove all the elements from LinkedHashSet in Java, use the clear() method.The following is an example to declare LinkedHashSet and add elements to it −LinkedHashSet hashSet = new LinkedHashSet(); hashSet.add(10); hashSet.add(20); hashSet.add(30); hashSet.add(40); hashSet.add(50); hashSet.add(60);Use the clear() method to remove all elements −hashSet.clear();The following is an example −Exampleimport java.util.LinkedHashSet; public class Demo { public static void main(String[] args) { LinkedHashSet hashSet = new LinkedHashSet(); hashSet.add(10); hashSet.add(20); hashSet.add(30); ...
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