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Page 249 of 589
How 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 shift array elements to the right
Let us first create an int array −int[] arr = { 10, 20, 30, 40, 50, 60, 70, 80, 90 };Now, shift array elements to the right with arraycopy() and placing the elements correctly so that it gets shifted to the right −System.arraycopy(arr, 0, arr, 1, arr.length - 1);Exampleimport java.util.Arrays; public class Demo { public static void main(String[] argv) throws Exception { int[] arr = { 10, 20, 30, 40, 50, 60, 70, 80, 90 }; System.out.println("Initial array..."+Arrays.toString(arr)); System.arraycopy(arr, 0, arr, 1, arr.length - 1); System.out.println("Array after shifting to the right..."); System.out.println(Arrays.toString(arr)); } }OutputInitial array... [10, 20, 30, 40, 50, 60, 70, 80, 90] Array after shifting to the right... [10, 10, 20, 30, 40, 50, 60, 70, 80]
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 generate random elements from a given array
Let’s say the following is our array −Integer[] arr = {2, 4, 6, 8, 10, 12, 14, 16, 18, 20};Now, we can convert it to a list before shuffling it −Listlist = Arrays.asList(arr); Collections.shuffle(list);The above shuffling generates random elements. Display them like this −for (Integer res: list) { System.out.print(res + " "); }Exampleimport java.util.Arrays; import java.util.Collections; import java.util.List; public class Demo { public static void main(String[] args) { Integer[] arr = {2, 4, 6, 8, 10, 12, 14, 16, 18, 20}; System.out.print("Array elements..."); for (Integer res: arr) { ...
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 MoreJava Program to convert java.util.Date to LocalDate
At first set the date with java.util.Date −java.util.Date date = new Date();Now, convert the date to LocalDate −Instant instant = Instant.ofEpochMilli(date.getTime()); System.out.println("LocalDate = "+LocalDateTime.ofInstant(instant, ZoneId.systemDefault()).toLocalDate());Exampleimport java.time.Instant; import java.time.LocalDateTime; import java.time.ZoneId; import java.util.Date; public class Demo { public static void main(String[] args) { java.util.Date date = new Date(); System.out.println("Date = "+date); Instant instant = Instant.ofEpochMilli(date.getTime()); System.out.println("LocalDate = "+LocalDateTime.ofInstant(instant, ZoneId.systemDefault()).toLocalDate()); } }OutputDate = Thu Apr 18 23:51:06 IST 2019 LocalDate = 2019-04-18
Read MoreJava Program to check if a Float is Infinite or Not a Number(NAN)
To check if a Float is isInfinite, use the isInfinite() method and to check for NAN, use the isNaN() method.Examplepublic class Demo { public static void main(String[] args) { float value1 = (float) 1 / 0; boolean res1 = Float.isInfinite(value1); System.out.println("Checking for isInfinite? = "+res1); float value2 = (float) Math.sqrt(9); boolean res2 = Float.isNaN(value2); System.out.println("Checking for isNan? = "+res2); } }OutputChecking for isInfinite? = true Checking for isNan? = false
Read MoreHow to display random numbers less than 20 in Java
At first, create a Random class object −Random rand = new Random();Now, create a new array −int num; int arr[] = new int[10];Loop through and set the Random nextInt with 20 as parameter since you want random numbers less than 20 −for (int j = 0; j
Read MoreSet Date value in Java HashMap?
Create a Calendar instance and Date object −Calendar cal = Calendar.getInstance(); Date date = new Date(); cal.setTime(date);Now, create a HashMap and store Date value −LinkedHashMaphashMap = new LinkedHashMap(); hashMap.put("year", cal.get(Calendar.YEAR)); hashMap.put("month", cal.get(Calendar.MONTH)); hashMap.put("day", cal.get(Calendar.DAY_OF_MONTH));Exampleimport java.util.Calendar; import java.util.Date; import java.util.LinkedHashMap; public class Demo { public static void main(String[] argv) { Calendar cal = Calendar.getInstance(); Date date = new Date(); System.out.println("Date = "+date); cal.setTime(date); LinkedHashMaphashMap = new LinkedHashMap(); hashMap.put("year", cal.get(Calendar.YEAR)); hashMap.put("month", cal.get(Calendar.MONTH)); hashMap.put("day", cal.get(Calendar.DAY_OF_MONTH)); ...
Read MoreHow to display numbers in scientific notation in Java?
To display number in scientific notation, create NumberFormat object first −NumberFormat numFormat = newDecimalFormat();Now, let’s say you need to format the minimum value of Integer −int i = Integer.MIN_VALUE; System.out.println(i); numFormat = newDecimalFormat("0.######E0"); System.out.println(numFormat.format(i)); numFormat = newDecimalFormat("0.#####E0"); System.out.println(numFormat.format(i));Above, we have used format() method of the NumberFormat class.Exampleimport java.text.DecimalFormat; import java.text.NumberFormat; public class Demo { public static void main(String args[]) { NumberFormat numFormat = new DecimalFormat(); int i = Integer.MIN_VALUE; System.out.println(i); numFormat = new DecimalFormat("0.######E0"); System.out.println(numFormat.format(i)); numFormat = new DecimalFormat("0.#####E0"); ...
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