How To Change The Length Of An Array In Java

Can you change size of Array in Java once created?

An array is a data construction/container/object that stores a fixed-size sequential drove of elements of the aforementioned blazon. The size/length of the assortment is adamant at the fourth dimension of cosmos.

The position of the elements in the array is called every bit index or subscript. The first element of the array is stored at the index 0 and, the second element is at the index ane and and then on.

Each element in an array is accessed using an expression which contains the name of the array followed by the index of the required chemical element in square brackets.

For example, if an assortment of 6 elements is created with proper noun myArray, you can access the element of the array at index iii as −

Organisation.out.println(myArray[3]); //25

Size of an assortment

In Java, arrays are treated as referenced types you can create an assortment using the new keyword similar to objects and populate it using the indices as −

The size of an array is fixed, if you lot create an array using the new keyword you demand to specify the length/size of information technology in the constructor as −

int myArray[] = new int[seven]; myArray[0] = 1254; myArray[one] = 1458; myArray[2] = 5687; myArray[3] = 1457; myArray[4] = 4554; myArray[5] = 5445; myArray[6] = 7524;

Y'all can as well direct assign values within bloom braces separating them with commas (,) as −

int myArray = {1254, 1458, 5687, 1457, 4554, 5445, 7524}; //size seven

If you create an array past initializing its values direct, the size will be the number of elements in information technology.

Thus the size of the array is adamant at the time of its creation or, initialization once information technology is done you cannot change the size of the array.

Still if yous try to assign value to the element of the array beyond its size a run time exception will be generated.

Example

In the post-obit case we are creating an assortment with 7 elements and modify nosotros are trying to assign value to the 8th chemical element.

public course Test {    public static void main(String[] args) {       int myArray[] = new int[7];       myArray[0] = 1254;       myArray[1] = 1458;       myArray[2] = 5687;       myArray[3] = 1457;       myArray[4] = 4554;       myArray[v] = 5445;       myArray[6] = 7524;       myArray[7] = 4238;       System.out.println(Arrays.toString(myArray));    } }

Run time error

Exception in thread "principal" coffee.lang.ArrayIndexOutOfBoundsException: vii at Test.principal(Test.java:13)

Changing the size of an array

You can alter the size of the existing array past reassigning it to the new i as −

Example

import coffee.util.Arrays; public class Test {    public static void main(String[] args) {       int myArray[] = new int[7];       myArray[0] = 1254;       myArray[1] = 1458;       myArray[2] = 5687;       myArray[iii] = 1457;       myArray[iv] = 4554;       myArray[5] = 5445;       myArray[6] = 7524;       Organisation.out.println(Arrays.toString(myArray));       myArray = new int[8];       myArray[0] = 1254;       myArray[one] = 1458;       myArray[2] = 5687;       myArray[3] = 1457;       myArray[4] = 4554;       myArray[5] = 5445;       myArray[six] = 7524;       myArray[7] = 3165;       System.out.println(Arrays.toString(myArray));    } }

Output

[1254, 1458, 5687, 1457, 4554, 5445, 7524] [1254, 1458, 5687, 1457, 4554, 5445, 7524, 3165]

In this scenario the earlier array object will exist left out for garbage collection. Thus, when used extensively this approach causes memory problems therefore, it is not recommended.

Published on 02-Aug-2019 14:26:49

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