Java Arrays deepToString()

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In this guide, you will learn about the Arrays deepToString() method in Java programming and how to use it with an example.

1. Arrays deepToString() Method Overview

Definition:

The Arrays.deepToString() method returns a string representation of the "deep contents" of the specified array. It's useful for arrays that contain other arrays as their elements.

Syntax:

String deepToString(Object[] a)

Parameters:

- a: The array whose deep-content representation is to be returned.

Key Points:

- It can handle arrays that contain other arrays to multiple levels of depth.

- If an element is an array of a primitive type, it gets converted directly to a string.

- If an element is an array of objects, it uses deepToString() recursively.

- It returns "null" if the array is null.

- Throws ArrayStoreException if any array contains itself.

2. Arrays deepToString() Method Example

import java.util.Arrays;

public class DeepToStringExample {
    public static void main(String[] args) {
        int[][] matrix = {
            {1, 2, 3},
            {4, 5, 6},
            {7, 8, 9}
        };

        String[] names = {"Alice", "Bob", "Charlie"};
        Object[] mixedArray = {matrix, names, "Hello, World!"};

        System.out.println("Matrix deep string representation: " + Arrays.deepToString(matrix));
        System.out.println("Mixed array deep string representation: " + Arrays.deepToString(mixedArray));
    }
}

Output:

Matrix deep string representation: [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
Mixed array deep string representation: [[[1, 2, 3], [4, 5, 6], [7, 8, 9]], [Alice, Bob, Charlie], Hello, World!]

Explanation:

The Arrays.deepToString() method is used to get a string representation of the deep contents of an array. In the example, we first convert a 2D integer array (matrix) to its string representation. Then, we create a mixed array containing the matrix, a string array, and a plain string. By using deepToString(), we can easily print nested arrays in a clear and formatted manner.