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Articles by karthikeya Boyini
Page 70 of 142
How to populate a 2d array with random alphabetic values from a range in Java?
To populate a 2d array with random alphabets, use the Random class. Let us first declare a 2d array −char arr[][] = new char[3][3];Now, in a nested for loop, use the Random class object to get random values on the basis of switch case. Here, our range is 3 i.e. set of 3 alphabets at once −Random randNum = new Random(); for (int i = 0; i < 3; i++) { for (int j = 0; j < 3; j++) { int x = randNum.nextInt(3); switch (x) { case ...
Read MoreJava Program to sort a subset of array elements
Let us first create a string array −String[] strArr = new String[] { "r", "p", "v", "y", "s", "q" };Now, use Arrays.sort() to get the subset. Use the following to sort only from the index range 2 to 6.Arrays.sort(strArr, 2, 6);Exampleimport java.util.Arrays; public class Demo { public static void main(String[] args) { String[] strArr = new String[] { "r", "p", "v", "y", "s", "q" }; Arrays.sort(strArr, 2, 6); System.out.println("Sorted subset of array elements from index 2 to 6..."); for (int a = 0; a < strArr.length; a++) ...
Read MoreJava Program to create an array with randomly shuffled numbers in a given range
For randomly shuffled numbers, let us create an integer list and add some numbers −List < Integer > list = new ArrayList < Integer > (); list.add(10); list.add(50); list.add(100); list.add(150); list.add(200);Now, shuffle the elements for random values −Collections.shuffle(list);Create an int array with the same number of elements in the above list −intlen = list.size(); int[] res = newint[len];Set the shuffled values in the new array −for (inti = 0; i < len; i++) { res[i] = list.get(i); }Exampleimport java.util.ArrayList; import java.util.Arrays; import java.util.Collections; import java.util.List; public class Demo { public static void main(String args[]) { ...
Read MoreHow to shuffle an array in Java?
Declare a string array and add elements in the form of letters −String[] letters = { "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z" };Convert the above array to list −Listlist = Arrays.asList(letters);Now, create a shuffled array using the Random class object and generate the random letters with nextInt() −int len = list.size(); System.out.println("Shuffled array..."); for (int i = 0; i < letters.length; i++) { int index = new Random().nextInt(len); String shuffle = list.get(index); System.out.println(shuffle); }Exampleimport java.util.Arrays; import java.util.List; import java.util.Random; public class Demo { public static void main(String[] args) { ...
Read MoreJava Program to generate random number array within a range and get min and max value
At first, create a double array −double[] val = new double[10];Now, generate and display random numbers in a loop that loops until the length of the above array. We have used nextInt here for random numbers −for (int i = 0; i < val.length; i++) { val[i] = new Random().nextInt(100); System.out.println(val[i]); }Now, get the min and max values. Compare each value of the random array with the MIN and MAX values −double min = Double.MAX_VALUE; double max = Double.MIN_VALUE; for (int i = 0; i < val.length; i++) { if (val[i] < min) min ...
Read MoreJava Program to get minimum value with Comparator
First, declare an integer array and add some elements −Integer arr[] = { 40, 20, 30, 10, 90, 60, 700 };Now, convert the above array to List −List list = Arrays.asList(arr);Now, use Comparator and the reverseOrder() method. Using max() will eventually give you the maximum value, but with reverseOrder() it reverses the result −Comparator comp = Collections.reverseOrder(); System.out.println("Minimum element = "+Collections.max(list, comp));Exampleimport java.util.Arrays; import java.util.Collections; import java.util.Comparator; import java.util.List; public class Demo { @SuppressWarnings("unchecked") public static void main(String args[]) { Integer arr[] = { 40, 20, 30, 10, 90, 60, 700 }; ...
Read MoreConvert from String to long in Java
To convert String to long, the following are the two methods.Method 1The following is an example wherein we use parseLong() method.Examplepublic class Demo { public static void main(String[] args) { String myStr = "5"; Long myLong = Long.parseLong(myStr); System.out.println("Long: "+myLong); } }OutputLong: 5Method 2The following is an example wherein we have used valueOf() and longValue() method to convert String to long.Examplepublic class Demo { public static void main(String[] args) { String myStr = "20"; long res = Long.valueOf(myStr).longValue(); System.out.println("Long: "+res); } }OutputLong: 20
Read MoreCheck that the String does not contain certain characters in Java
Let’s say the following is our string with special characters.String str = "test*$demo";Check for the special characters.Pattern pattern = Pattern.compile("[^A-Za-z0-9]"); Matcher match = pattern.matcher(str); boolean val = match.find();Now, if the bool value “val” is true, that would mean the special characters are in the string.if (val == true) System.out.println("Special characters are in the string.");Exampleimport java.util.regex.Matcher; import java.util.regex.Pattern; public class Demo { public static void main(String []args) { String str = "test*$demo"; System.out.println("String: "+str); Pattern pattern = Pattern.compile("[^A-Za-z0-9]"); Matcher match = pattern.matcher(str); boolean val = ...
Read MoreNegate a BigInteger in Java
Use the BigInteger negate() method in Java to negate a BigInteger.First, let us create an object −BigInteger one, two; one = new BigInteger("200");Negate the above and assign it to the second object −two = one.negate();The following is an example −Exampleimport java.math.*; public class BigIntegerDemo { public static void main(String[] args) { BigInteger one, two; one = new BigInteger("200"); System.out.println("Actual Value: " +one); // negate two = one.negate(); System.out.println("Negated Value: " +two); } }OutputActual Value: 200 Negated Value: -200
Read MoreJava Program to format to 2 decimal places in a 10-character field
To format, use the Formatter class. Import the following package to work with the Formatter class in Java −import java.util.Formatter;Create a Formatter object and format to 2 decimal places in a 10-character field −Formatter f = new Formatter(); System.out.println(f.format("%10.2e", 3989.7886));The following is the complete example −Exampleimport java.util.Formatter; public class Demo { public static void main(String args[]) { Formatter f = new Formatter(); System.out.println(f.format("%08d", 697)); f = new Formatter(); System.out.println(f.format("%03d", 9878)); f = new Formatter(); System.out.println(f.format("%10.2e", 3989.7886)); } }Output00000697 9878 3.99e+03
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