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Java Articles
Page 36 of 450
Modify the value associated with a given key in Java HashMap
First, create a HashMap and add elements to it −// Create a hash map HashMap hm = new HashMap(); // Put elements to the map hm.put("Bag", new Integer(1100)); hm.put("Sunglasses", new Integer(2000)); hm.put("Frames", new Integer(800)); hm.put("Wallet", new Integer(700)); hm.put("Belt", new Integer(600));Now, to modify the value associated with a given key, use the put() method. Here, we are modifying the value for the key “Frames” −hm.put("Frames", "900");The following is an example to modify the value associated with a given key −Exampleimport java.util.*; public class Demo { public static void main(String args[]) { // ...
Read MoreCheck two HashMap for equality in Java
To check whether two HashMap are equal or not, use the equals() method.Let us first create the first HashMap −// Create hash map 1 HashMap hm1 = new HashMap(); hm1.put("Shirts", new Integer(700)); hm1.put("Trousers", new Integer(600)); hm1.put("Jeans", new Integer(1200)); hm1.put("Android TV", new Integer(450)); hm1.put("Air Purifiers", new Integer(300)); hm1.put("Food Processors", new Integer(950));Let us now create the second HashMap −HashMap hm2 = new HashMap(); hm2.put("Shirts", new Integer(700)); hm2.put("Trousers", new Integer(600)); hm2.put("Jeans", new Integer(1200)); hm2.put("Android TV", new Integer(450)); hm2.put("Air Purifiers", new Integer(300)); hm2.put("Food Processors", new Integer(950));To check whether both the HashMap are equal or not, use the equals() method like this −hm1.equals(hm2)The following is ...
Read MoreFind minimum element of HashSet in Java
To get the minimum element of HashSet, use the Collections.min() method.Declare the HashSet −Set hs = new HashSet();Now let us add the elements −hs.add(29); hs.add(879); hs.add(88); hs.add(788); hs.add(456);Let us now get the minimum element −Object obj = Collections.min(hs);The following is an example to find the minimum element of HashSet −Exampleimport java.util.*; public class Demo { public static void main(String args[]) { // create hash set Set hs = new HashSet(); hs.add(29); hs.add(879); ...
Read MoreGet Enumeration over HashSet in Java
To get enumeration over HashSet, first declare the HashSet and add elements −HashSet hs = new HashSet(); hs.add("P"); hs.add("Q"); hs.add("R");To get enumeration −Enumeration e = Collections.enumeration(hs);The following is an example to get Enumeration over HashSet −Exampleimport java.util.*; public class Demo { public static void main(String[] args) { HashSet hs = new HashSet(); hs.add("P"); hs.add("Q"); hs.add("R"); Enumeration e = Collections.enumeration(hs); while (e.hasMoreElements()) System.out.println(e.nextElement()); } }OutputP Q R
Read MoreAdd elements to LinkedHashMap collection in Java
Use the put() method to add elements to LinkedHashMap collection.First, let us create a LinkedHashMap −LinkedHashMap l = new LinkedHashMap();Now, add elements −l.put("1", "Jack"); l.put("2", "Tom"); l.put("3", "Jimmy"); l.put("4", "Morgan"); l.put("5", "Tim"); l.put("6", "Brad");The following is an example to add elements to LinkedHashMap collection −Exampleimport java.util.LinkedHashMap; public class Demo { public static void main(String[] args) { LinkedHashMap l = new LinkedHashMap(); l.put("1", "Jack"); l.put("2", "Tom"); l.put("3", "Jimmy"); ...
Read MoreCreate NavigableMap in Java
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 themExampleimport 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 MoreLoop through ArrayList in Java
The elements of the ArrayList can be accessed one by one by using a for loop. A program that demonstrates this is given as followsExampleimport java.util.ArrayList; import java.util.List; public class Demo { public static void main(String[] args) { ArrayList aList = new ArrayList(); aList.add("Sun"); aList.add("Moon"); aList.add("Star"); aList.add("Planet"); aList.add("Comet"); System.out.println("The ArrayList elements are:"); for (String s : aList) { System.out.println(s); } } }OutputThe output of the above program ...
Read MoreNavigableSet Class ceiling() method in Java
The ceiling() method returns the least element greater than or equal to the given element i.e. 30 hereceiling(30)The following is an example to implement the ceiling method in JavaExampleimport 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.ceiling(30)); } }OutputReturned Value = 40
Read MoreInsert all elements of other Collection to Specified Index of Java ArrayList
The elements of a Collection can be inserted at the specified index of the ArrayList using the method java.util.ArrayList.addAll(). This method has two parameters i.e. the specific index at which to start inserting the Collection elements in the ArrayList and the Collection itself.If there is an element already present at the index specified by ArrayList.addAll() then that element and all subsequent elements are shifted to the right to make the space for the Collection elements in the ArrayList.A program that demonstrates this is given as follow.Exampleimport java.util.ArrayList; import java.util.Vector; public class Demo { public static void main(String[] args) { ...
Read MoreSet vs HashSet vs TreeSet in Java
A Set is a generic set of values with no duplicate elements. A TreeSet is a set where the elements are sorted.A HashSet is a set where the elements are not sorted or ordered. It is faster than a TreeSet. The HashSet is an implementation of a Set.Set is a parent interface of all set classes like TreeSet, HashSet, etc.Exampleimport java.util.*; public class Demo { public static void main(String args[]) { int a[] = {77, 23, 4, 66, 99, 112, 45, 56, 39, 89}; Set s = new HashSet(); try ...
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