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Articles by karthikeya Boyini
Page 9 of 143
Extract values from HashMap in Java
To extract values from HashMap, let us first create a HashMap with keys and values −HashMapm = new HashMap();Now, add some elements to the HashMap −m.put(10, 20); m.put(30, 40); m.put(50, 60); m.put(70, 80); m.put(90, 100); m.put(110, 120); m.put(130, 140); m.put(150, 160);Now, extract the values from the HashMap −for (Integer i: m.keySet()) { System.out.println(m.get(i)); }Exampleimport java.util.HashMap; public class Demo { public static void main(String args[]) { HashMapm = new HashMap(); m.put(10, 20); m.put(30, 40); m.put(50, 60); m.put(70, 80); m.put(90, 100); ...
Read MoreProvider toString() method in Java
The name and the version number of the provider in string form can be obtained using the method toString() in the class java.security.Provider. This method requires no parameters and it returns the name as well as the version number of the provider in string form.A program that demonstrates this is given as follows −Exampleimport java.security.*; import java.util.*; public class Demo { public static void main(String[] argv) { try { KeyPairGenerator kpGenerator = KeyPairGenerator.getInstance("DSA"); Provider p = kpGenerator.getProvider(); System.out.println("The name and version number of the ...
Read MoreJava Program to loop through Map by Map.Entry
Create a Map and insert elements to in the form of key and value −HashMap map = new HashMap (); map.put("1", "A"); map.put("2", "B"); map.put("3", "C"); map.put("4", "D"); map.put("5", "E"); map.put("6", "F"); map.put("7", "G"); map.put("8", "H"); map.put("9", "I");Now, loop through Map by Map.Entry. Here, we have displayed the key and value separately −Sets = map.entrySet(); Iteratori = s.iterator(); while (i.hasNext()) { Map.Entrye = (Map.Entry) i.next(); String key = (String) e.getKey(); String value = (String) e.getValue(); System.out.println("Key = "+key + " => Value = "+ value); }Exampleimport java.util.HashMap; import java.util.Iterator; import java.util.LinkedHashMap; import java.util.Map; import ...
Read MoreProvider getService() method in Java
The service that can describe the implementation of a Provider in regards to any algorithm is obtained using the method getService() in the class java.security.Provider. This method requires two parameters i.e. the service type required and the algorithm name of the required service.A program that demonstrates this is given as follows −Exampleimport java.security.*; import java.util.*; public class Demo { public static void main(String[] argv) throws Exception { try { Signature sign = Signature.getInstance("SHA256withDSA"); Provider p = sign.getProvider(); Provider.Service s = p.getService("Signature", sign.getAlgorithm()); ...
Read MoreJava Program to display a prime number less than the given number
Let’s say the value you have set is 20 and you have to display a prime number less than this value i.e. 19 in this case.The following is an example that displays a prime number less than the given number −Examplepublic class Demo { public static void main(String[] args) { int val = 20; boolean[] isprime = new boolean[val + 1]; for (int i = 0; i
Read MoreProgram to calculate area and perimeter of Trapezium
Trapezium is a type of quadrilateral that has at least one pair of side parallel to each other. Area and perimeter of a trapezium can be found using the below formula, Perimeter = sum of all sidesArea = ½ x (sum of the lengths of the parallel sides) x perpendicular distance between parallel sidesCode logic − The code will use 5 variables in as all sides of trapezium and one for the perpendicular distance between the two parallel side. For the area variable calculation we will take a float variable that will be initialised with the value. To calculate it ...
Read MoreProgram to calculate the area of an Circle inscribed in a Square
A circle inscribed in a square is a circle which touches the sides of the circle at its ends. I.e. the diameter of the inscribed circle is equal to the side of the square. The area can be calculated using the formula “((丌/4)*a*a)” where ‘a’ is the length of side of square.Logic of the Code - The area of circle inscribed inside the circle is calculated using the formula ((丌/4)*a*a) for this we need to define the value of pie (丌) that mathematically is 22/7 or 3.14. The expression that evaluates to the result is saved in a float variable.Example#include ...
Read MoreProgram to calculate area of Circumcircle of an Equilateral Triangle
A circumcircle is a circle that inscribes a regular polygon inside it. The triangle that is inscribed inside a circle is an equilateral triangle. Area of circumcircle of can be found using the following formula, Area of circumcircle = “(a * a * (丌 / 3))”Code Logic, The area of circumcircle of an equilateral triangle is found using the mathematical formula (a*a*(丌/3)). The value of 丌 in this code is coded as 3.14. The expression is evaluated into a float value.Example#include #include int main(){ int a = 5; float area; float pie = 3.14; ...
Read MoreJava Program to insert a value to a SortedSet
Let’s say we have the following SortedSet −SortedSet set = new TreeSet(); set.add("T"); set.add("R"); set.add("S"); set.add("Q"); set.add("V"); set.add("U"); set.add("W");Now, after displaying the above elements with Iterator, you can insert values like this to a SortedSetset.add("Z"); set.add("Y");Exampleimport java.util.Iterator; import java.util.SortedSet; import java.util.TreeSet; public class Demo { public static void main(String[] argv) throws Exception { SortedSet set = new TreeSet(); set.add("T"); set.add("R"); set.add("S"); set.add("Q"); set.add("V"); set.add("U"); set.add("W"); Iterator i = set.iterator(); ...
Read MorePattern matching in Python with Regex
What is Regular Expression?In the real world, string parsing in most programming languages is handled by regular expression. Regular expression in a python programming language is a method used for matching text pattern.The “re” module which comes with every python installation provides regular expression support.In python, a regular expression search is typically written as:match = re.search(pattern, string)The re.search() method takes two arguments, a regular expression pattern and a string and searches for that pattern within the string. If the pattern is found within the string, search() returns a match object or None otherwise. So in a regular expression, given a ...
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