Slice an Array in Java

1. Array Slicing in Java
2. Slice an Array by Duplicating Elements in Java
3. Slice an Array Using the copyOfRange() Method in Java
4. Slice an Array Using the Java 8 Stream

This article will help you slice an array into a subarray in Java.

Array Slicing in Java

Array slicing is a Java technique for extracting a subarray from a more extensive array.

Assume that k[] is an array. It has 7 components, numbered k[0] through k[6].

k[] = {5, 6, 7, 8, 9, 10, 11}

Now, we’re looking for a slice of the array index between k[2] and k[5]. The startIndex is k[2], while the endIndex is k[5].

As a result, we obtain the sliced array below:

k[] = {7, 8, 9, 10}

In the following sections, we’ll learn how to locate an array slice in Java.

Slice an Array by Duplicating Elements in Java

It’s a built-in way to acquire a slice of an array. The start and end indexes of the provided array are initially determined in this procedure.

After that, we generate a size-independent empty array (sliced array) (endIndex - startIndex). Copy the items (from startIndex) from the provided array to the sliced array, and lastly, print the sliced array.

Let’s use the way described above in a Java program to acquire a sliced array of the supplied array. We’ll utilize an array of primitive kinds in this application.

import java.util.Arrays;

public class Copy {

    public static int[] getSlice(int[] arr, int stIndx, int enIndx) {

        int[] sclicedArr = new int[enIndx - stIndx];

        for (int i = 0; i < sclicedArr.length; i++) {
            sclicedArr[i] = arr[stIndx + i];
        }

        return sclicedArr;
    }

    public static void main(String args[]) {

        int[] arr = { 20, 65, 87, 19, 55, 93, 76, 98, 54, 21 };

        int stIndx = 2, enIndx = 6;

        int[] sclicedArr = getSlice(arr, stIndx, enIndx + 1);

        System.out.println("Slice of an Array: " + Arrays.toString(sclicedArr));
    }
}

To run the code, save the program as a Java file and run it in your Java IDE.

Output:

Slice an Array Using the copyOfRange() Method in Java

The Java Array class contains the copyOfRange() method. It replicates the array’s stated range to a newly formed array (slice array) and returns the newly produced array with the original array’s specified range.

Slicing an array requires O(n) time and O(n) space to store the elements, where n is the number of elements in the resultant array.

Syntax:

public static int[] copyOfRange(int[] original, int from, int to)

The following 3 parameters are parsed by the method:

• original: It is an array with a slice that must be found.
• from: It is the index for the first page. It must be in the range of 0 to the array’s length.
• to: It is the last index.

The following exceptions are thrown:

If the start index is less than 0 or higher than the length of the original array, an ArrayIndexOutOfBoundsException will be thrown. If the start index is more significant than the end index, an IllegalArgumentException will be thrown.

If the specified array is null, a NullPointerException will be thrown.

import java.util.Arrays;

public class Copy1 {

    public static int[] slice(int[] arr, int stIndx, int enIndx) {

        int[] sclicedArr = Arrays.copyOfRange(arr, stIndx, enIndx);

        return sclicedArr;
    }

    public static void main(String args[]) {

        int[] arr = { 20, 65, 87, 19, 55, 93, 76, 98, 54, 21 };
        int stIndx = 3, enIndx = 8;

        int[] sliceArray = slice(arr, stIndx, enIndx + 1);

        System.out.println("Slice of Array: " + Arrays.toString(sliceArray));
    }
}

To run the code, save the program as a Java file and run it in your Java IDE.

Output:

Slice an Array Using the Java 8 Stream

We may use the Java 8 Stream to discover the slice of an array by following the instructions below.

import java.util.Arrays;
import java.util.stream.IntStream;

public class NewClice {

    public static int[] findSlice(int[] arr, int stIndx, int enIndx) {

        int[] slice_arr = IntStream.range(stIndx, enIndx).map(i -> arr[i]).toArray();

        return slice_arr;
    }

    public static void main(String args[]) {

        int[] arr = { 20, 65, 87, 19, 55, 93, 76, 98, 54, 21, 657 };
        int stIndx = 2, enIndx = 8;

        int[] slice_arr = findSlice(arr, stIndx, enIndx + 1);

        System.out.println("Slice of array for the specific range is: " + Arrays.toString(slice_arr));
    }
}

To run the code, save the program as a Java file and run it in your Java IDE.