Question

How to get array subset in Java

Answer 1

import java.util.Arrays;

public class ArraySubset {
    public static void main(String[] args) {
        int[] arr = {3, 7, 9, 0, 4, 2, 1, 8};
        int startIndex = 2; // Start index for the subset
        int length = 4; // Number of elements in the subset

        // Extract subset using Arrays.copyOfRange
        int[] subset = Arrays.copyOfRange(arr, startIndex, startIndex + length);

        System.out.println("Subset: " + Arrays.toString(subset));
    }
}


/*
run:

Subset: [9, 0, 4, 2]

*/

 

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Answer 2

import java.util.Arrays;

public class ArraySubset {
    public static void main(String[] args) {
        int[] arr = {3, 7, 9, 0, 4, 2, 1, 8};
        int startIndex = 2; // Start index for the subset
        int length = 4; // Number of elements in the subset

        int[] subset = new int[length];
        for (int i = 0; i < length; i++) {
            subset[i] = arr[startIndex + i];
        }

        System.out.println("Subset: " + Arrays.toString(subset));
    }
}


/*
run:

Subset: [9, 0, 4, 2]

*/

 

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Answer 3

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

public class ArraySubset {
    public static void main(String[] args) {
        int[] arr = {3, 7, 9, 0, 4, 2, 1, 8};
        int startIndex = 2; // Start index for the subset
        int length = 4; // Number of elements in the subset

         // Extract subset using streams
        int[] subset = IntStream.range(startIndex, startIndex + length)
                                .map(i -> arr[i])
                                .toArray();

        System.out.println("Subset: " + Arrays.toString(subset));
    }
}


/*
run:

Subset: [9, 0, 4, 2]

*/

 

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