Programming Articles - Page 2897 of 3366

HashSet is a class in Java that implements the Set interface. It is used for storing unique elements. Our task is to check if a HashSet contains another collection in Java. Let's look at some scenarios to understand the problem better: Scenario 1 Input: {1, 2, 3, 4, 5} Collection to check: {2, 3} Output: true Explanation: The HashSet contains all the elements of the collection {2, 3}. Scenario 2 Input: {1, 2, 3, 4, 5} Collection to check: {6, 7} Output: false Explanation: The HashSet does not contain all the elements of the collection {6, 7}. Checking ... Read More

To fetch the value for a specific key, use the get() method.As a parameter, set the key you want to fetch and fetch the value.Let’s say you need to fetch value of key 3get("3")The following is an example to fetch the value for a specific key in Java IdentityHashMap −Example 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);       m.put("5", 110);       m.put("6", 50); ... Read More

Use the remove() method to remove an element from IdentityHashMap.Let us create IdentityHashMap and add some elementsMap 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);Let’s say you need to remove 2 from the Map. For that, use the remove() methodm.remove("2");The following is an example to remove an element from Java IdentityHashMapExample Live Demoimport java.util.*; public class Demo {    public static void main(String[] args) {       Map m = new IdentityHashMap(); m.put("1", 100); ... Read More

Check whether a Map is empty or not using the isEmpty() method.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, use the following method to check whether the Map is empty or not. Since we added some elements above, therefore the Map is not emptyn.isEmpty();Example Live Demoimport java.util.*; public class Demo {    public static void main(String[] args) {       Map m = new IdentityHashMap(); m.put("1", 100); m.put("2", 200); m.put("3", 300); m.put("4", 150); ... Read More

The floorKey() method is used to get floor key i.e. to return the greatest key less than or equal to the given key, or null if there is no such key.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);       n.put("D", 988);       n.put("E", 686);       n.put("F", 888);       n.put("G", 999);       ... Read More

The first and last elements of a Linked List can be obtained using the methods java.util.LinkedList.getFirst() and java.util.LinkedList.getLast() respectively. Neither of these methods require any parameters.A program that demonstrates this is given as followsExample Live Demoimport java.util.LinkedList; public class Demo { public static void main(String[] args) { LinkedList l = new LinkedList(); l.add("John"); l.add("Sara"); l.add("Susan"); l.add("Betty"); l.add("Nathan"); ... Read More

The lowerEntry() method in NavigabelMap returns a key-value mapping associated with the greatest key strictly less than the given key.The following is an example to implement lowerEntry() methodExample Live Demoimport 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");       n.put(4, "Jackie");       n.put(15, "Kurt");       n.put(19, "Tiger");       n.put(24, "Jacob");       System.out.println("NavigableMap elements..."+n);       System.out.println("Lower Entry is ... Read More

The higherEntry() method in NavigableMap returns a key-value mapping associated with the least key strictly greater than the given key.The following is an example to implement higherEntry() method −Example Live Demoimport 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");       n.put(4, "Jackie");       n.put(15, "Kurt");       n.put(19, "Tiger");       n.put(24, "Jacob");       System.out.println("NavigableMap elements..."+n);       System.out.println("Higher Entry ... Read More

The ModuleFinder class in 'modulefinder' module can determine set of modules imported by a certain script. This module has a command line interface as well as programmatic interface.For demonstration of functionality, use following script#modfinder.py import hello try: import trianglebrowser import nomodule, mymodule except ImportError: passCommand line interfaceFollowing command displays list of modules located as well as not found.E:\python37>python -m modulefinder modfinder.pyOutputName File ---- ---- m __main__ modfinder.py m hello hello.py m math m trianglebrowser trianglebrowser.py Missing modules: ? mymodule imported from __main__ ? nomodule imported from __main__Programmatic interfaceModuleFinder class in ... Read More

Automatic garbage collection is one of the important features of Python. Garbage collector mechanism attempts to reclaim memory occupied by objects that are no longer in use by the program.Python uses reference counting mechanism for garbage collection. Python interpreter keeps count of number of times an object is referenced by other objects. When references to an object are removed, the count for an object is decremented. When the reference count becomes zero, the object memory is reclaimed.Normally this mechanism is performed automatically. However, it can be done on purpose if a certain situation arises in the program. The 'gc' module ... Read More